What was going on when I was born?

A senior Kremlin official said today that Moscow's latest proposal to reduce medium-range missiles meant that the weapons would be removed from the European part of the Soviet Union, not that all within reach of Europe would be removed. The question is of some importance to Western negotiators, since the Soviet Union's SS-20 medium-range missiles have a range of more than 3,000 miles and could hit targets in Western Europe even if emplaced in Asia, east of the Urals, which is the conventional eastern boundary of Europe. Moreover, the weapons are transportable and could be moved westward, albeit with some difficulty, in times of crisis. The official, Leonid M. Zamaytin, said the disposition of the missiles to be dismantled west of the Urals would be an issue for negotiation.

As senators juggled flight schedules and holiday plans, supporters of a bill to raise the Federal gasoline tax by 5 cents a gallon lobbied frantically for votes today and predicted victory when the legislation reaches a showdown in the Senate Thursday morning. President Reagan called some key Senators from the White House, while Howard H. Baker Jr. of Tennessee, the Senate majority leader, organized teams of assistants to keep a tight rein on lawmakers straining to get home for Christmas. Military planes will be available to fly senators back to Washington if they are needed, according to an aide to the Senate leadership. One possible passenger is Senator Barry Goldwater, Republican of Arizona, who has been in poor health but says he intends to return to Capitol Hill for the vote.

The General American Oil Company of Texas, fighting a $520 million takeover bid by the Mesa Petroleum Company, disclosed last night a counteroffer for its own stock in a move that could start a bidding war. General American said that it would buy up to 8 million of its own shares, or 31 percent of those outstanding, for $50 each. It also reserved the right to purchase an additional 5 million shares.

A report in New York Day by Day on Monday about a bird count in Brooklyn incorrectly gave the number of species identified. It was 112, including either a bald or a golden eagle.

''The fare is saved.'' - Richard Ravitch. (A1:6.)

FEW years ago, as John and Sarina Mascheroni were celebrating Christmas at their house in East Hampton, L.I., they asked their housekeeper to take the ornaments off the tree and pack them up. ''She saw it as a challenge,'' Mr. Mascheroni recalled. ''But she stopped counting at 1,000,'' he said, because there were so many. ''I call it my tree of memories,'' said Mrs. Mascheroni, fashion director for home furnishings at the Associated Merchandising Corporation, a national retail buying group. ''I put everything on it but the kitchen sink,'' she said. ''We almost always run out of time before we run out of ornaments.'' Decorating the tree usually takes two days, she added.

Congress has renewed an order barring the Reagan Administration from supporting military operations aimed at overthrowing the Nicaraguan Government. Administration officials said today that the Defense Department and the Central Intelligence Agency were complying with the order. The measure, approved by the House and the Senate, forbids the United States from providing ''military equipment, military training or advice, or other support for military activities, for the purpose of overthrowing the Government of Nicaragua or provoking a military exchange between Nicaragua and Honduras.'' Reagan to Push Aid Program ''We are complying with the law now and will continue to do so,'' a White House official said. The renewal of the order was contained in an emergency spending bill signed by President Reagan on Tuesday. On Dec. 8, the House approved a measure containing the same prohibition. That measure, which was presented in the form of an amendment to the Intelligence Authorization Act of 1983, was approved 411 to 0. Supporters called it a symbolic vote of no confidence in the Central Intelligence Agency.

Richard P. Cooley, who resigned Tuesday as chairman and chief executive officer of Wells Fargo & Company, yesterday was named chairman, president and chief executive officer of the troubled Seafirst Corporation of Seattle. Seafirst, the nation's 26th-largest bank holding company, is less than half the size of Wells Fargo, the 12th largest. Moreover, Wells Fargo, which is based in San Francisco, has an international reputation, while Seafirst is basically a regional organization. At the end of 1981, Seafirst's assets amounted to $10.8 billion, compared with $23.2 billion for Wells Fargo.

Dr. Barney B. Clark took a few short, shuffling but encouraging steps today in his struggle as the first human to live with a permanent artificial heart. A University of Utah Medical Center spokesman, John Dwan, said Dr. Clark Mr. Dwan added that the patient must still be regarded as being in critical health but that he was beginning to approach a more normal conditon. ''What we have seen in the last two or three days is what we should phrase as a return to normalcy, both on the part of Dr. Clark, his family and the hospital staff,'' Mr. Dwan said. He said he could recall as many as 11 doctors in Dr. Clark's room at one time in the hectic days after the artificial heart was implanted Dec. 2. But now, Mr. Dwan said, Dr. Clark may be seen ''sitting in a chair looking out the window,'' with a nurse sitting outside his room at a desk doing paper work and with no one else around.

The State Financial Control Board yesterday approved New York City's four-year financial plan, but warned that many obstacles remained on the city's path to full fiscal health. The unanimous vote for the plan, which covers the fiscal years 1983 through 1986, followed months of wrangling over whether the Koch administration had a balanced budget for this year and a reasonable chance of balancing the next three budgets. Twice before - in June and November - the Control Board declined to give its approval.

The oil and gas business moves this city, but what has irked Denver's retailers the most in the past few days are the unseasonal 50- and 60-degree temperatures that have slowed sales of outerwear and ski apparel. Soon enough, maybe before Saturday, the snow and colder weather that characterize Christmas here will return. But the larger problem for the region and its retailers, the slump in the energy industry, is likely to last a lot longer. Earlier this year, retail sales here were slowed by employment declines in the oil and gas business. Since November, however, those sales have improved. Today, while traffic was active into the big downtown stores on the new 16th Street pedestrian mall, many shoppers paused first to enjoy the sunshine, to eat ice cream and to gaze at the sundry public characters who flock to midtown areas.

As the special session of Congress limps to an inconclusive end, there is some question of whether the next Congress can deal with the acute problems of the economy any better than they were dealt with this year. The question is critically important now because much of the power to deal with the economy has shifted from the White House to Capitol Hill. This uncertainty is now beginning to overshadow the widespread promises of a recovery early next year. Economists continue to forecast a recovery then, but these predictions are slowly slipping from modest to muted to anemic growth, leaving the nation's unemployment rate perhaps as high as 10 percent by the end of 1983. Only the outlook for inflation improves, as the affliction of the 1970's is tamed by four years of economic stagnation, the longest since the Great Depression.