What was going on when I was born?

Clayton K. Yeutter, the United States trade representative, said today that President Reagan ''almost assuredly'' will veto legislation on textile import quotas that is likely to be the first of some 300 protectionist bills to reach the White House in the current trade ferment. Although the President has declared his general intention to veto protectionist bills, Mr. Yeutter's statement, in response to a question in a televised interview, was the first by any Administration official singling out a specific measure. It was the latest example of a more aggressive trade strategy that is emerging from the White House to counter the growing protectionist sentiment on Capitol Hill. While brandishing the veto threat, the Administration also now plans a more aggressive stand against countries that refuse to open their markets to foreign competition.

The Economy A veto of legislation on textile import quotas is almost assured, Clayton K. Yeutter, the United States trade representative, believes. The bill is likely to be the first of some 300 pending protectionist bills to reach the White House. [Page D1.]

Hundreds of high school girls in New York City and its suburbs, eager for athletic competition, are playing regularly on boys' sports teams. Some of the girls welcome the mixed play as a more formidable challenge, but most would have no opportunity without it. The coed teams are almost exclusively in noncontact sports, such as tennis, cross-country and golf, according to athletic officials in New York, New Jersey and Connecticut. ''In these types of noncontact sports, the girls do very well,'' said Robert F. Kanaby, executive director of the New Jersey State Interscholastic Athletic Association. ''If schools can't provide separate programs, the next best thing is for schools to allow girls into these boys' sports.''

As he approaches his second anniversary as chairman of the Metropolitan Transportation Authority, Robert R. Kiley says he has learned a thing or two about running the world's largest mass transit system. He says he has learned that New York is bigger - much bigger - than Boston. He has learned, he says, that there is more to running a railroad than good management. And, he says, he has learned not to throw away buses without making a phone call first. Mr. Kiley, who used to run Boston's mass transit system, acknowledges that even a man deeply versed in government and politics, Boston-style, can have a lot to learn when he starts dealing with government and politics, New York-style.

International Postponement of a Senate vote scheduled this week on a bill placing economic sanctions against South Africa will be sought by the Senate majority leader, Bob Dole, because President Reagan is expected to agree to put most of them into effect administratively. The expected announcement by Mr. Reagan and the move to delay a vote could avoid a major confrontation between the President and the Republican-controlled Senate. [Page A1, Column 6.] President P. W. Botha opposes reported plans of leading South African business executives to meet with the outlawed and exiled African National Congress. He said such actions were ''disloyal,'' and strongly denied that he had given his approval for such talks with the rebel group. [A8:1.]

A military faction this morning seized Thailand's armed forces headquarters and announced on Radio Thailand that it had overthrown the Government. Within hours, a tank battle erupted in Bangkok in an area of Government and military offices. By midmorning, officers loyal to the Government of Prime Minister Prem Tinsulanonda announced on armed forces radio and television that they had regained control and that the coup had been put down. But fighting between army factions was still going on at midday. The loyalist faction announced a state of emergency and told everyone to return home and stay in their homes.

After a private weekend retreat in the Virginia countryside, Treasury Department officials and leaders of the House Ways and Means Committee said today they were optimistic they could work together to write legislation restructuring the Federal income tax system. At a joint news conference, Treasury Secretary James A. Baker 3d said that President Reagan's commitment to tax revision was ''total'' and ''unswerving'' and that ''at the very least, there's a fair shot'' of accomplishing the goal this year. The committee chairman, Representative Dan Rostenkowski, said the weekend session indicated that all sides had the ''patience and flexibility and bipartisanship'' to work together.

A dispatch from Tegucigalpa, Honduras, Saturday on the delivery of 12 American helicopter gunships to the Salvadoran Air Force misstated the size of their guns. The helicopters are equipped with 7.62-millimeter machine guns.

''Tell Patterson I'm gonna buy him a steak dinner.'' - Pete Rose after tying Ty Cobb's record for base hits. [A1:3.]

The people of Clay County live in a variety of houses along the creeks and rivers deep inside the Daniel Boone National Forest. Some live in sleek ranch-style houses; others in mobile homes or the ancient, sagging shacks that have served generations of mountain families. For although the Federal Government has spent billions of dollars over the past 25 years to change the face of poor rural communities here and elsewhere, the miseries of inadequate shelter persist for a large portion of the rural population. Meanwhile, the flow of Federal housing assistance funds is slowing. The Reagan Administration is committed to getting the Government out of housing construction and has sought to abolish the Farmers Home Administration, the agency that provides most rural housing aid. So far, the agency has survived but Congress cut its budget for the fiscal year beginning next month by 41 percent, to $2.1 billion.

For the first time in Ronald Reagan's Presidency, Congress has abruptly seized the initiative on foreign policy matters and has placed the White House on the defensive on several key, politically charged issues, White House and Congressional officials say. Mr. Reagan's announcement, scheduled for Monday, on his plans for some economic sanctions against South Africa is a reluctant bow to Congressional pressure and comes after considerable debate within the White House. On Saturday Mr. Reagan responded to aggressive bipartisan Congressional pressure to limit foreign imports by announcing moves against several major American allies for ''unfair trading practices.'' These actions - coupled with earlier compromises with Congress on nonmilitary aid to Nicaraguan rebels, a limit of 50 MX nuclear missiles to be deployed in existing silos and trims in the increase in military spending -are a major departure from relations with Congress in Mr. Reagan's first term.

Of the major groups of the population that can claim injury from the failings of the nation's economy, farmers would rank high. But in the view of members of both the Administration and Congress, a multibillion-dollar Federal rescue of one group of farmer-bankers - a bailout possibly dwarfing the rescues of the Continental Illinois National Bank and the Chrysler Corporation - would do little to relieve the economic pressures facing farmers. Such aid, they said, might only favor a single group, the farmer-owners of the network of 800 cooperative lenders known as the Farm Credit System. Other farmers and farm bankers lack the political voice of the cooperatives, which are organized, albeit loosely, in nearly every congressman's district, all under the umbrella of their Government overseer, the Farm Credit Administration. Farmers have taken a disproportionate share of the harmful side effects of the economy's enormous changes during the 1980's, notably the strong dollar and high interest rates that economists attribute to the big Federal budget deficits that have dogged the nation since early in the Reagan presidency.