What was going on when I was born?

''On distant islands in the South Atlantic young men are fighting for Britain.

Like two families planning a wedding, the New York City Police and the sponsors of Saturday's disarmament demonstration have been meeting day after day to check -and sometimes tactfully negotiate - the final arrangements. The police, who expect up to half a million people to converge on the city for the rally, said the planning had taken a month of meetings. During these sessions, the two sides have negotiated everything from the police plan to have mounted officers patrol the rally to the organizers' request that they issue their own parking permits and that two of the city's trees be cut down. Although the police denied some requests, they did agree to set aside 100,000 of the best spots at the rally for actual demonstrators, as opposed to music fans out for a day's entertainment.

Argentine warplanes bombed and damaged the British frigate Plymouth and two landing ships tonight, causing at least five casualties, the Defense Ministry announced. In the first intensive combat between British ships and enemy jets in the Falkland Islands war in 10 days, two Argentine aircraft were shot down, the ministry said in a statement issued just before midnight. At least five planes were reported damaged, with one possibly destroyed. In Buenos Aires, the Argentine command said tonight that its planes had attacked British forces making an amphibious landing at Pleasant Bay, 16 miles southwest of Stanley, the islands' capital, sinking a frigate and damaging three landing craft. (Page A22.)

Once again, the General Electric Company is going it alone in lobbying Congress on taxes. It opposes the Administration and most of big business on tax leasing. It opposes the Administration's proposal to strengthen the corporate minimum tax, although it has not joined a coalition of 20 companies also opposed. In a move that set tongues wagging in Washington tax circles, G.E. recently retained a high-powered lobbyist and political fund-raiser, J.D. Williams. In all, as Congress searches for ways to raise revenue and shrink future budget deficits, G.E. is living up to its reputation as a special presence in the tax-lobbying arena. ''A lot of companies come and go in the tax fight but G.E. is one that stands out all the time,'' says one of Washington's best-known tax lobbyists, who asked not to be identified.

Israeli tank columns and infantry units pushed as far as 32 miles into Lebanon today, driving toward Beirut from two directions in an apparent attempt to trap as many Palestinian guerrillas as possible. One advance column was said to have reached the village of Baruk, 15 miles southeast of Beirut. The Beirut radio said the column was exchanging fire tonight with troops of the Syrian peacekeeping force who were on the Beirut-Damascus highway about eight miles to the north. A Syrian military spokesman said Syrian tanks, helicopter gunships and artillery clashed with the Israelis at several points in central Lebanon. But thus far the Syrians appear to have refrained from throwing the full weight of their armed forces into battling the Israelis.

FULLERTON, Calif. IN a cluster of rooms fronting on a courtyard beneath the palm trees at Griswold's Inn here, 40 expert palates were sequestered for three days in May, tasting some 1,400 California wines in a ritual with implications for consumers and producers alike. The tasters were judges in the annual Orange County Fair wine competition, and they were deciding which wines should be awarded gold, silver or bronze medals. Their decisions, often later upgraded by a steering committee that actually awarded the prizes, had a rapid impact, although the results were not immediately announced and the fair does not open in Costa Mesa until July 9. Wineries that won gold medals are bracing for the surge in sales that always occurs following a major competition, and consumers able to ferret out the names of winners are already stocking up. The Orange County Fair is but one of a growing number of wine competitions that are an emerging national phenomenon with an ever greater influence on the wine-consuming public. Nobody seems to know just how many there are across the country, but the contests are outgrowths of the American wine boom, evolving from a handful of informal judgings in the 1960's and early 70's into complex events at which hundreds of wines are rated in many categories.

International Israeli forces moved toward Beirut, converging on Lebanon's capital from two directions in an apparent attempt to trap as many Palestinian guerrillas as possible. As Israeli units progressed northward along the Shouf mountain range running through central Lebanon they ran into large concentrations of Syrian peacekeeping troops. A Syrian military spokesman said Syrian tanks, helicopter gunships and artillery attacked the Israelis at several points. (Page A1, Column 6.) The U.S. vetoed a resolution voted by all 14 other members of the Security Council of the United Nations that threatened Israel with sanctions for refusing to halt its invasion of Lebanon. (A1:6.)

Israeli and Syrian planes and troops clashed today, but Israeli officials said the Syrians had not entered the battle in force. Prime Minister Menachem Begin called publicly on President Hafez al-Assad of Syria to refrain from engaging the Israelis. The Israeli Chief of Staff, Lieut. Gen. Rafael Eytan, said Israeli jet fighters shot down six Syrian MIG's today, three over Beirut, one over Damur and two over the Galilee panhandle of northern Israel. One Syrian pilot who ejected from his plane was reported captured.

President Reagan urged Britain and the world today to join the United States in a crusade for freedom by encouraging the spread of democracy, even in Communist countries. The President adopted a militantly anti-Communist tone. He described the Soviet Union as an economic failure that might be on the brink of famine except for the output of the tiny private element in the nation's agricultural sector. And he challenged Leonid I. Brezhnev, the Soviet leader, to a peaceful struggle for ideological supremacy.

The Cities Service Company yesterday rejected two takeover bids from the Mesa Petroleum Company and offered to sweeten its own offer for Mesa. Provided Mesa would support it, Cities Service said it was prepared to raise its offer by $4, to $21 a share, for a 51 percent interest. It proposed a stock swap for the rest, offering 0.45 share, currently equivalent to about $16, for each remaining share of Mesa. The new proposal, announced by the chairman of Cities Service, Charles J. Waidelich, at a news conference, was conveyed in a letter to T. Boone Pickens Jr., chairman of Mesa. The revised bid was not made public until 4:30 P.M., however, at the request of the American Stock Exchange. It asked that the news conference be delayed until after the day's trading in options had ended.

As Connecticut's flooding emergencies began to ease today, state and Federal officials intensified their efforts to get Federal aid to help repair the still uncalculated damage caused by the weekend deluge. Gov. William A. O'Neill, declaring that ''the basic emergency situation has ended,'' said he would meet with his Cabinet Thursday to put together an overall damage estimate. Once that estimate is compiled, the state will send its formal application to President Reagan for Federal disaster assistance such as low-interest loans to help rebuild homes and businesses. The preliminary steps to get the assistance were already under way. James Sanders, administrator of the United States Small Business Administration, surveyed some of the damage by helicopter today with the Governor and several members of the Congressional delegation.

When the man walked in to her specialty food shop on Lexington Avenue near 93d Street the other day, Linda Deme was hunched over a counter, drafting a petition to Capt. John J. Murphy, the commander of the 23d Precinct. Mrs. Deme, like 165 other store owners and residents who eventually signed the petition, was disturbed that the only foot patrolman who walked a beat in the neighborhood had been transferred to another trouble spot in the Upper East Side-East Harlem precinct. ''We want a patrolman back on Lexington Avenue as soon as possible,'' Mrs. Deme was writing as the neatly attired man who had just entered her shop, the Country Host, drew nearer. ''Please be a nice young lady and empty your cash register,'' he said nonchalantly, as she recalled it later. The man kept his right hand in his pocket, and Mrs. Deme put down her pen. She had always thought that, if she were held up, the robber would be disheveled and would terrify her with a loud ''Stick 'em up!'' It wasn't happening that way, but, even if the voice was carefully modulated, the hand in the pocket was menacing.