What was going on when I was born?

The vanguard of the British battle fleet is less than a week's sailing time from the Falkland Islands, military sources indicated today. The sources said that the last warships of the task force left the rendezvous point off Ascension Island, in midocean between Africa and South America, sometime early Thursday. Other elements of the main British flotilla, which consists of about 25 ships, were reported to have left the area as early as last Monday or Tuesday, headed toward the South Atlantic. It appears that the fleet is making about 18 or 19 knots, which means it will take the ships about seven or eight days to complete the voyage from Ascension to the South Atlantic, where nuclearpowered submarines of the Royal Navy are enforcing a blockade in a 200-mile zone around the Falklands.

President Reagan said today that his Administration's budget negotiations with Congress were ''approaching a climactic stage,'' and he promised a ''constructive and conciliatory spirit'' in deciding whether to compromise on his economic program. ''We must join together to bring down deficits, bring down interest rates and revive the economy,'' Mr. Reagan told a group of editors and broadcasters from the Southeast in what White House Reagan remarks are on page 9. aides interpreted as yet another conciliatory signal to Congress that he might be prepared to shift his position on the budget. The next budget negotiation session between the White House and Republican and Democratic Congressional leaders is scheduled for Sunday afternoon, and what aides said would be a final session is scheduled for Tuesday.

Prime Minister Menachem Begin received a letter today from President Hosni Mubarak of Egypt and was officially described as satisfied and pleased by the message. The Prime Minister's press secretary, Uri Porat, said Mr. Begin believed Egypt and Israel would be able to resolve their differences and ''there is no reason to reconsider the Israeli Government's resolution to complete the withdrawal or evacuation on time.'' The optmistic statement, which came in a flurry of diplomatic efforts to ease Egyptian-Israeli tensions, represented an abrupt shift in the mood from earlier in the week, when some Israeli officials were talking of postponing the withdrawal from Sinai because of what they called Egyptian violations of the treaty. The pullout is scheduled for April 25.

Under pressure from farmers, the Reagan Administration has agreed to hold talks with the Soviet Union on grain sales, the first since the imposition of martial law in Poland last December. The announcement of the meeting, to take place in Paris on May 21 and 22, was made today by Senator Bob Dole, Republican of Kansas, and Senator Roger W. Jepsen, Republican of Iowa. They called it ''a vital and necessary step toward restoring normal grain trade relations between the two countries and in strengthening United States farm prices.'' Administration officials took a less dramatic view: They said that under the current Soviet-American grain supply agreement, which is to expire Sept. 30, the two sides are supposed to hold twice-a-year consultations.

The handling of the Falkland crisis by the United States Government has provoked deep resentment in Britain. The Argentines have also been critical of the United States, charging that it was favoring Britain. But a broad cross section of Britons have been offended by what they feel is the lack of more overt support by senior American officials, including President Reagan and Secretary of State Alexander M. Haig Jr. Perhaps the greatest outrage has been directed at Jeane J. Kirkpatrick, the delegate to the United Nations, for attending a dinner at the Argentine Embassy on April 2, the day of the Argentine seizure of the Falkland Islands.

A Reagan Administration plan to help reduce the national deficit by selling Federal lands to private bidders threatens to ignite a new controversy over public land policy in the West. The opposition is likely to come not only from environmentalists but also from ranchers and politicians who so far have enthusiastically supported the President and Interior Secretary James G. Watt. Although the Administration has not worked out the final details of its proposal, the mere specter of Federal land sales in a region where the Federal Government owns nearly 50 percent of the land has provoked alarm. Those expressing apprehension include ranchers who fear that the Federal land they have used as grazing pasture will be sold to the highest bidder, as well as private real estate speculators and state land managers, who worry that large-scale sales of public land could depress property prices throughout the region. ''This question of privatizing public lands is like taking a big stick and stirring everything up again,'' said Gregg Cawley, a political scientist at the University of Wyoming in Laramie. He is a specialist in the movement, commonly called the ''sagebrush rebellion,'' that involves Westerners opposed to what they believe is restrictive Federal control over the use of public lands and resources in their region.

The president of the New York Public Library was standing at his desk, routinely going through his mail one recent morning, when he came across an enclosure that made him sit down, stupefied. ''I thought it was a check for $10,000,'' the official, Dr. Vartan Gregorian, said later. ''Then I looked again and it was a check for $1 million.'' The check came from the estate of William C. Helmle, an engineer and an evidently modest man about whom little is known. According to his lawyer, Mr. Helmle worked for the American Telephone and Telegraph Company for 31 years and retired some time in the 1950's. He died childless in 1979 at the age of 84. His wife, Helen May, had died some years before. Mr. Helmle's estate was valued at about $3 million.

Health officials in New York City and Connecticut yesterday advised people not to eat any Alaskan salmon from 7 3/4-ounce cans. They acted after doctors in Hartford said that a 68-year-old woman who apparently ate such salmon had contracted botulism. The advisory followed the recall by the United States Food and Drug Administration of 7 3/4-ounce cans bearing scores of different serial codes. But the F.D.A. did not recall all cans of that size. The recall was ordered April 8. A spokesman for the F.D.A. said yesterday that there were no plans to broaden the recall.

The Chinese Government warned today that Chinese-American relations remained at a critical stage over the Taiwan arms issue and that it was possible that they could worsen. The assertion, made today in a front-page commentary in the official People's Daily, seemed designed at least in part to assure Chinese readers that their Government had not given in to the Reagan Administration by failing to retaliate against its decision to sell military spare parts to Taiwan. ''Now, the relations between China and the United States are still at a critical juncture and the crisis of a likely retrogression of the relations exists, because the question of the United States selling of arms to Taiwan remains unsettled,'' said the commentary, which was circulated in full by the New China News Agency to give further exposure. The Reagan Administration notified China on Tuesday that it was presenting a $60 million package of aircraft spare parts and other supplies for Taiwan to Congress.

Occupied Sinai, April 15 - Amid pain and defiance, Israel is dismantling its presence in the last area of the Sinai Peninsula still under its control, in preparation for returning it to Egypt in 10 days. Most settlers who over the last decade had wrought prosperity from the desert have left, taking with them all that they could carry from their houses and holdings. But Vito and Ella Weizman's house, the ivy-like creepers on its walls gray with the dust of the destruction around it, stands incongruously intact in this abandoned town where 72 families lived until recently. While cranes and bulldozers were at work around the settlement, dismantling what they could, demolishing what they could not, Mrs. Weizman, who is 32 years old, the mother of four children and pregnant, received a visitor in her living room. The normality of the room made it look abnormal in this town. ''How exactly it will be, I honestly don't know,'' Mrs. Weizman said, when asked what she and her family would do when the army comes to remove them sometime before April 25. ''One thing is definite - that I will not leave this house of my own free will.''

President Reagan's special envoy in the negotiations for Israel's final withdrawal from the Sinai Peninsula arrived in Cairo from Israel today. Deputy Secretary of State Walter J. Stoessel Jr., who came for two days of talks with President Hosni Mubarak and other key Egyptian officials, said in an airport statement that ''I am hopeful that my visit and recent meetings between Egypt and Israel will result in the resolution of present difficulties.''

An 18-year-old Soviet Jew chained himself to a fence around St. Basil's Cathedral in Red Square today and held up a sign demanding permission to immigrate to Israel. The police quickly seized him.