What was going on when I was born?

''The Tower'' - a musical theater piece by the Pulitzer prizewinning composer Michael Colgrass - will be given its American premiere on Roosevelt Island tonight at 8 by 20 schoolchildren. Roosevelt Island? Schoolchildren? Yes. The musical, a modern, urban version of ''Jack and the Beanstalk,'' was written to be performed by children. Nancy Breth, a pianist who lives on the island, planned and raised funds for the community event. The Canadian composer auditioned and helped in rehearsals. Various professional people, including Diana Baffa Brill, a choreographer who is directing the work, donated their time. The site is the Chapel of the Good Shepherd on Main Street. Tickets are $4 ($2 for children, the elderly and the handicapped). Information: 753-6889 or 371-4642. UKRAINIAN 7TH ST. FESTIVAL Seventh Street, between Second and Third Avenues, will be closed to traffic and open to celebrants today, tomorrow and Sunday for the fifth annual festival sponsored by the St. George Ukrainian Catholic Church. Ukrainian dancers and singers will perform. Ethnic foods - pierogi, kolbasa, stuffed cabbage and home-baked pastries -will be available. So will crafts, including embroideries, wood carvings, ceramics and Easter eggs. And booths will offer games of chance. Hours: 4 to 11 P.M. today, 11 A.M. to 11 P.M. tomorrow and 1 to 10 P.M. on Sunday.

The United States petroleum industry is fast reaching a consensus that crude oil is too expensive, and a dozen oil companies have reduced the price they will pay for a barrel of domestically produced oil by an average of $2 a barrel. Conoco Inc. announced yesterday that it was cutting its posted buying price for crude by $2 in most parts of the United States, effective today. And so far this week, Texaco, the Sun Company, Ashland Oil, Standard of Ohio, Husky Oil, Marathon, Pennzoil and Dorchester Gas have cut their prices by an average $2 a barrel, to a range of $34 to $36 in most cases. These reductions follow similar moves last week by Cities Service, Phillips Petroleum and Standard of Indiana. Other companies are considering similar actions. For example, Atlantic Richfield said yesterday, ''We are reviewing our position. However, we have not made a decision as yet.'' Shell Oil said it was ''constantly'' reevaluating its posted prices.

The cargo freighter Atra is a troubled ship. Her hold is full of unsold scrap metal, her fuel tanks and food lockers are almost empty and her bridge is plastered with liens from creditors, including her crew, which has not been paid since March. The saga of the Atra, now at a berth on Staten Island, has led the freighter since the turn of the year from New Brunswick, Canada, to New Haven - where a ''rampage'' by a previous crew all but disabled her - and finally to New York. She has been detained at Staten Island since mid-February, first by the Coast Guard and then by legal action from her creditors.

A news analysis May 7 on the Inter- national Brotherhood of Teamsters in- correctly characterized the state of health of Jackie Presser, a vice presi- dent of the union. Mr. Presser is in good health.

An operation financed by four insurance companies has led to four arrests and the recovery of more than $200,000 in stolen gold and silver jewelry, guns, electronic equipment and other valuables, Connecticut's Attorney General said today. The ''sting on a shoestring,'' as the Attorney General, Francis M. McDonald, called it, also led to the issuance of warrants for the arrest of 20 other persons. The undercover operation was financed through the Insurance Crime Prevention Institute, with contributions of $5,000 each from the Travelers Insurance Companies, the Connecticut General Insurance Company, the Hartford Insurance Company and Aetna Life and Casualty.

''We will continue to try just as long as our efforts would make a constructive contribution.

The credit markets were surpised by a quick rally that raised some long-term bond prices more than 2 1/2 points. Most analysts attributed the rebound to technical factors such as short covering by speculators. Some Treasury bill rates fell by about a quarter of a percentage point. (Page D1.) The assets of money market funds have started to decline after 17 consecutive weeks of growth, according to figures reported by the Investment Company Institute. Their yields have lagged behind those on competing investments. (D1.)

The credit markets were suprised yesterday afternoon by a quick rally. One trader called it a ''nervous spasm,'' but it was nevertheless strong enough to raise some long-term bond prices more than 2 1/2 points. Most analysts attributed the rebound, which also reduced some Treasury bill rates by about a quarter of a percentage point, to technical factors, such as short covering by speculators. In the financial futures markets, where speculative positions can be taken with very little cash, the anticipation of a drop in rates from current high levels was great enough to lift prices sharply for Treasury bill and bond contracts.

The Sony Corporation, whose stock was spurned by American investors through the late 1970's, today has regained its once-lustrous image as a coveted issue. A surge in profits last year, a firm foothold in the video market and some promising new-product offerings have combined to give Sony what Wall Street brokers are fond of calling ''glamour,'' Indeed, the last time Sony has possessed such stature was more than a decade ago, when its Trinitron entry was rushing ahead in the color television market. ''The American investor is starting to realize that Sony is more than a high-quality television producer,'' said Mark Hassenberg, an analyst for Donaldson, Lufkin & Jenrette. ''People are beginning to view Sony as a multinational, high-technology corporation.''

WHAT has evolved into the city's quintessential neighborhood celebration, that extended block party known as the annual Ninth Avenue International Festival, arrives for the eighth consecutive year this weekend, promising once again to be a high-spirited sampler of New York's many ethnic identities and their foods. Tomorrow and Sunday, from 11 A.M. to 7 P.M., rain or shine, Ninth Avenue from 37th to 57th Street will become one vast ethnic kitchen in which, between belly dances and polkas and appearances by Mayor Koch and Borough President Andrew Stein of Manhattan, visitors can choose from among such traditional foods as Polish sausage, Greek spinach pie, Italian pasta, pancit Canton, a cooked noodle concoction from the Philippines; Middle Eastern falafel, a fried bean croquette; kimchi, a Korean pickled cabbage dish; chunks of sugar cane from Barbados, Taiwanese pineapple, and boorek, a Turkish drink made from honey and nuts. Ninth Avenue will be closed to automobile traffic both days to permit visitors - there were 500,000 last year -to wander along the avenue, sampling the food, watching puppets and clowns tomorrow, and on Sunday viewing a variety of entertainment on three stages. In addition to the sidewalk food stands, neighborhood restaurants and stores will serve up their specialties, from kebabs to quiches. The Port Authority of New York and New Jersey, whose bus overpass crosses Ninth Avenue, is co-sponsor of the festival and will provide bands to listen to and benches to rest on.

The head of the antiterrorist squad at the Rome police headquarters was quite sure this morning what sort of man he was dealing with in Mehmet Ali Agca, the Turkish youth who is accused of trying to assassinate Pope John Paul II yesterday. ''He is a terrorist with a capital 'T,' cold, lucid and certainly well trained to shoot,'' said Alfredo Lazzarini, after the 23-yearold alleged assailant had undergone more than 12 hours of uninterrupted questioning. But it was much less clear to the Italian authorities who had trained Mr. Agca, who had helped him to escape from prison in Turkey, who had paid for his wanderings through Europe and who had provided him with the forged documents that concealed his identity. Nor was it clear whether Mr. Agca - his name is pronounced ADJ-ah - is a man of the left or of the right. Leaflet Found in Suspect's Pocket The police have arrested no one else. They are convinced, according to Government sources, that Mr. Agca acted alone - in the sense that he had no accomplices with him in St. Peter's Square and none, in all probability, elsewhere in Rome or in Italy. Mr. Agca himself insisted that the attack was his own idea and his own responsibility.

VISITORS to New York's two major art auction houses will have an opportunity to see paintings valued at $60 million this weekend before they are put up for sale next week. Among the more than 1,000 works are paintings by Degas, van Gogh, Cezanne, Gauguin, Matisse, Picasso and Renoir that are expected to sell for $1 million or more each. Adding to the interest in these sales is the fact that four of the million dollar paintings come from a collection of eight works whose owner has chosen not to disclose his identity. There is also a controversial Picasso, a 1912 piece from the artist's Cubist period, that he is said to have refused to sign after it had been relined and restored. These paintings will be up for bidding starting at 8 P.M. Tuesday at Christie's, Park Avenue at 59th Street. So will a suite of eight paintings by Magritte that is expected to bring up to $2 million. The Matisse is up for sale Monday night, also at Christie's. A second Picasso and two Renoirs will be auctioned Thursday at Sotheby's, Madison Avenue at 59th Street. Both galleries are displaying the paintings - two of New York's biggest free art shows of the year - today and tomorrow from 10 A.M. to 5 P.M. and on Sunday from 1 to 5 P.M.