What was going on when I was born?

The Reagan Administration was reported today to have tentatively decided on enlarging its program of arms sales to Saudi Arabia by including five Awacs electronic surveillance planes and seven KC-135 aerial tankers. In addition, the Administration was said by officials and Congressional sources to be prepared to leave in Saudi Arabia four Air Force Awacs craft operating there, until five such planes to be sold to the Saudis can be delivered in 1985. This tentative decision was made, officials said, at a National Security Council meeting yesterday. Vice President Bush presided at the meeting in the absence of President Reagan.

The Federal Trade Commission today charged Volkswagen with failing to disclose potential engine problems in more than one million of its cars. The commission said that Volkswagen of West Germany and its American subsidiary ''knew or should have known'' that an ''abnormally high'' number of their water-cooled automobiles in the model years from 1974 to 1979 used too much oil and required expensive repairs. It said that the law required that ''owners or prospective owners'' be informed of such potential repair problems. Volkswagen of America later issued a statement contending that the charges were ''without factual or legal support.'' The commission's action marks the fourth time that it has filed a complaint that an automobile manufacturer has failed to disclose important information about reliability, durabilty or maintenance. It is the first case of this type against a foreign manufacturer and importer.

IN a splash of chromatic overstatement that makes spring blooms seem pallid, that nomadic tribe called the Ringling Brothers and Barnum & Bailey Circus opened for a nine-week stay at Madison Square Garden on Wednesday with a 26-act, two-hour-and-57-minute extravaganza, the ususal dizzying panopoly of pyrotechnics designed to numb the brain and unfocus the eye. This circus, in what they call its 111th edition, is a little different each year, yet always the same. Audiences grow up into it and grow up out of it, and the proper age for the circus depends upon one's capacity to be thunderstruck, astonished, elated, awed, pleasantly fearful and otherwise generally impressed. It is an experience in which the mind must cope with everything rather than any one thing, and the spectator carries away a mentally engraved pastiche of sound, motion and color.

A court-appointed psychiatrist has found John W. Hinckley Jr. competent to stand trial in the shooting of President Reagan, but a Federal judge today ordered a more extensive mental examination, which could take from 30 to 90 days. The 25-year-old defendant, wearing a bulletproof vest, appeared in Federal District Court today for two separate hearings that lasted a total of slightly more than 40 minutes. Security was extremely tight. Dr. James L. Evans, the court-appointed psychiatrist, examined Mr. Hinckley for three hours yesterday. Dr. Evans's report, released by the court today, was that Mr. Hinckley was ''mentally competent to stand trial,'' that he had ''a rational and factual understanding of the charges and is able to participate with counsel in the preparation of his defense.'' Deals Only With Competence However, such a finding deals only with the suspect's competence to stand trial and does not deal with the question of sanity at the time of the shooting. Nor does it preclude a plea of not guilty by reason of insanity.

The Republican-dominated Senate approved a $36.9 billion package of spending reductions by a vote of 88 to 10 tonight, thereby ordering an extensive retrenchment in social welfare programs and a change in the direction of government. The Democrats in the Senate nevertheless introduced dozens of foredoomed amendments, to put themselves and the Republicans on record on issues ranging from funds for veterans to childhood immunization. The measure now goes to the Democratic-controlled House, whose leaders predicted that the President would get about 75 percent of what he asked, compared with the more than 100 percent that was voted by the Senate. The Senate cuts were $2.8 billion deeper than those recommended by the President.

International New American food aid to Poland was pledged by Vice President Bush. He told a high Polish official visiting Washington that the United States would provide $70 million worth of surplus butter and dried milk to help ease Warsaw's deepening economic crisis. (Page A1, Column 1.) Bonn urged Soviet moderation in international affairs. At a wideranging meeting in Moscow, Hans-Dietrich Genscher, the West German Foreign Minister, said that Bonn would consider Soviet intervention in Poland a flagrant violation of the 1975 Helsinki accord on human rights and East-West relations in Europe. (A3:1-3.)

Governor Carey and Evangeline Gouletas, the Chicago condominium developer, announced today that only their families would attend their wedding ceremony next week. The ceremony will take place on April 11, the Governor's 62d birthday, at the Holy Trinity Greek Archdiocesan Cathedral on East 74th Street in Manhattan, according to a person familiar with the plans. The wedding will be a Greek Orthodox rite. The Greek Orthodox Church permits members who have obtained ecclesiastical divorces to be married again in the Church.

The General Public Utilities Corporation, facing possible bankruptcy because of the Three Mile Island accident, won permission yesterday to increase substantially rates charged by its two Pennsylvania subsidiaries. Analysts said the increase, which would generate additional annual revenues of $106.7 million, could give the utility more time to solve its financial problems, although the amount was less than G.P.U. had requested. 'Needs Money to Survive' ''The company needs this money to survive,'' a spokesman for the Pennsylvania Public Utilities Commission said. The commission unanimously voted to approve the rate increases, the first the two subsidiaries have received since 1978.

Jan De Gaetani, the mezzo-soprano, has a reputation for versatility. Tonight at 8:30, she will sing music spanning the centuries, from Handel and Brahms to Vaughan Williams and Arnold Black, at the Rockland Center for the Arts, 27 Greenbush Road, West Nyack, N.Y. Assisting artists will be Philip West, oboist; Abba Bogin, pianist and harpsichordist, and Frederick Zlotkin, cellist, who will also perform the Poulenc Sonata for Oboe and Piano and Beethoven's Seven Variations on a Theme by Mozart for cello and piano. Tickets are $5.50 ($4.50 for students and the elderly). Reservations are suggested: (914) 358-0877. SATIRE ON THE WEST SIDE An antic look at joggers, the mayoral race, liberals, transitory love and answering machines, among other things, will be offered tonight when ''Late City Edition'' - a satirical revue of city life that ran briefly at the Symphony Space in January - reopens there as a regular late-night cabaret. The revue, which will run each Friday and Saturday at 11:15 through June, will include songs, sketches and poetry by such writers as Eve Merriam, Russell Baker and Isaiah Sheffer, who is the director of the cabaret. He also produced the DMZ cabaret at the Village Vanguard a decade ago. There will be new material as well as bits from the first ''Late City Edition.'' Known and not-so-well known performers will join the four-member cast from time to time. At Broadway and 95th Street. Tickets are $5. Reservations: 865-2557.

DRIVING northward from Paris toward Chantilly on the new expressway, you can't miss the Cathedral of St.-Denis, though it lies quite some way from the road. And if it's conspicuous now, with its high-backed silhouette and its look of a great ship that has somehow drifted inland, we may be sure that it was even more conspicuous in the year 1144, when it was inaugurated with all possible pomp in the presence of Louis VII, King of France, his queen, Eleanor of Aquitaine, and everyone who counted in France. Seen in the context of that plainest and flattest of countrysides, it must have stood out like a diamond on a dungheap. The cathedral as it stood in the 12th century was the creation of one of the most brilliant men of his day - or for that matter, of any day - in France. This year marks the 900th anniversary of his birth. Now and through May 31 we can see at the Cloisters an exhibition that has been devised in his honor. Its full title is ''The Royal Abbey of St.-Denis in the time of Abbot Suger,'' and it includes monumental sculptures, panels of stained glass and sumptuous liturgical objects, every one of which can be traced to the great church in its early days.

Egyptians say they oppose U.S. role in Sinai force A2 U.S. terminates economic aid to Nicaragua A3 Around the World A6 For Istanbul youth, return to farm is not a way out A7 In Shanghai, mute reminders of China's break with the past A8 Khomeini seeks purges of judici- ary and revolutionary guards A9 Polish union ousts official A10 West German Foreign Minister due in Moscow today A11 Second Islamic peace effort in Gulf seems to end in failure A11 Yuri Trifonov, writer, given offi- cial funeral in Moscow A12 Quebec nationalists take unex- pected lead in poll A16 Reagan Shooting President is moved to private hos- pital room A22 Sen. Kennedy ready to compro- mise to pass gun control bill A22 Government/Politics Chicago Mayor's first night in ghetto housing is 'very quiet' A18 Koch reported about to replace Board of Standards head B3 Representative Rosenthal ques- tions advertising by Invsco B5 Navy drops contract for 9th Tri- dent submarine at Groton B10 General Around the Nation A18 Former People's Temple aide con- fessed to 5 killings A20 Judge refuses to delay trial in slaying of Dr. Halberstam A21 Nursing-home strike is postponed- after progress in talks B2 Education/Welfare Boston postpones shutdown of public school system A18 Brzezinski returns to Columbia B3 News Analysis Richard Eder on foreign reaction to Reagan shooting A25 Editorials/Letters/Op-Ed Editorials A26 Swords into sausage for Poland Whom the coal strike will hurt Love for sale Topics: cold/dry Letters A26 William Safire: only one, Secre- tary Haig, fell short A27 Anthony Lewis: out of a lonely crowd, an assassin A27 Stanley O. Day: the Liberian coup through 'bifocals' A27 Michael R. Gordon: arms and inflation A27

year-old soprano from Urbana, Ill., scooped three bent nails from a backstage floor - traditional tokens of good fortune. Gail Dubinbaum, 25, a mezzo from Northridge, Calif., did not dare think of winning for fear of invoking a jinx. And Rebecca Cook, 28, a soprano from San Francisco, battled a thought that intruded on her concentration as she sang ''Dove sono'' from ''The Marriage of Figaro'' on stage. ''Dear God,'' Miss Cook kept thinking, ''I'm at the Met!'' The three young singers, as it turned out, need not have worried. They were among 11 singers named winners of the annual auditions held at the Metropolitan Opera House last Sunday by the opera's National Council as the culmination of a yearly hunt for grassroots talent. The 11 will appear in a concert of solo and ensemble works this Sunday at 2 on the Metropolitan Opera stage - an event that could help their careers as well as their self-esteem, because agents interested in young talent are sure to be in the audience. The public can judge their talent for itself; tickets are $5 to $10. (Information: 799-3100). In addition, on Wednesday, three of the 11 will perform from noon to 1 in a free concert at St. Peter's Lutheran Church, 617 Lexington Avenue. Each of the 11 will receive a $3,000 study grant.