What was going on when I was born?

LESS than 10 years ago, assistants in the Suffolk County Attorney's office, many of them political appointees, worked out of their private law offices, with the county paying half their rent and half the salary of a secretary. Now, confronted with a growing caseload, the County Attorney's office has taken on the trappings of professionalism, with all the assistants in county buildings, although most of the 43 attorneys are still political appointees. William Kent, the chief deputy county attorney, said that major factors behind the growing caseload were the county's changeover to self-insurance in most cases and the tangle of Federal regulations, particularly in social services. The office, he said, was handling cases from the prosecution of juvenile delinquents to the defense of major negligence suits.

Until yesterday, only three horses in this century had won the Belmont Stakes by more than 10 lengths: Secretariat, Count Fleet and Man o' War. Now there is a fourth, and if he keeps running the way he did yesterday, he may someday be mentioned in the same breath as those three thoroughbred idols. Conquistador Cielo, who ran the fastest mile in the history of Belmont Park only six days ago, was leading a top field of 3-yearolds by only a head after the first mile of the 114th Belmont Stakes yesterday at Belmont Park. Half a mile and 50 4/5 seconds later, he crossed the finish line under Laffit Pincay Jr., 14 1/2 lengths ahead of Gato del Sol, the Kentucky Derby winner. The track was reduced to a sea of mud by downpours Friday night and yesterday afternoon, but nobody was making excuses. ''Nothing would have made a difference today,'' said Eddie Delahoussaye, who rode the runner-up. ''The winner was just too much.''

WHILE Connecticut's six United States Representatives are busy shuttling between Washington and their districts, watching the political developments at home and preparing a record in office on which they can seek re-election, they are facing a difficult, confusing and overdue piece of business that will probably reach the top of the agenda later this week: the 1983 budget. The House of Representatives was supposed to make the basic decisions about the budget last month, before the Memorial Day recess, voting on a ''budget resolution'' that would lay out the broad outlines of tax and spending changes. But with three proposed resolutions before them - one from each of the parties and one bipartisan effort - the Representatives failed to reach agreement before they left the Capitol. However, in a series of interviews with The New York Times just before the recess began, the state's six Representatives and two Senators showed a surprising degree of agreement on several outstanding issues.

For several months it has been taking shape behind whitewashed windows at 1191 Third Avenue, looking to passersby like yet another boutique aborning in a neighborhood of boutiques. But now the windows have been washed clean, a uniformed guard is at the door and everyone can see what the first new private safe-deposit vault in New York City in 20 years looks like.

The ink stain on the front of George Bamberger's shirt, right under where it says Mets, was a sign that he had been doodling during the game tonight. The 6-2 loss to the Reds was the fourth straight defeat for the Mets, tied their longest losing streak of the year, and was evidence that some changes were in order. The names Bamberger scribbled on the back of tonight's lineup card formed tomorrow's lineup. The Mets manager would not say whose names would be on the dugout wall Sunday, but he did say there would be changes.

WITH the growth of high-technology industry on the Island, and the Federal Government's increased spending for defense, there has been a recent resurgence of demand for engineers here. Four of the Island's largest employers of engineers - Grumman, Sperry, Fairchild Republic and Eaton - are actively recruiting graduates from the Island's three engineering schools, as well as conducting national searches for more highly skilled engineers, mainly in the fields of electronics and computer sciences. According to the New York State Department of Labor, there were 28,200 engineering positions available in Nassau and Suffolk Counties in 1974. But next year, the Labor Department estimates, there will be 33,000 engineering positions on the Island. A recent study of some 70 Long Island high-technology companies done by the Regional Industrial Technical Education Council indicates that the number of engineers and computer science personnel with four-year degrees who will be needed on the Island by 1986 will increase by 36 percent, and the number of engineering technicians with two-year degrees needed will increase by 47 percent.

TRENTON ALTHOUGH the State Department and a member of the Congressional Black Caucus are pressing for full disclosure, some New Jersey officials say that the results of a State Police investigation of charges made by a Nigerian diplomat may never be fully known. The diplomat, Ngam Nwachuku, Senior First Secretary in the Nigerian Mission to the United Nations, said that last Feb. 27, after he had tried to get directions from a trooper parked on the shoulder of I-287 in Middlesex County, he and his wife were dragged from their car and taken to the State Police barracks in Edison. In the next two and a half hours, Mr. Nwachuku said, two troopers repeatedly called him a ''nigger,'' handcuffed him and his wife and ransacked their Mercedes-Benz while they stood outside in the cold with their 2 1/2-year-old son. Mr. Nwachuku said that they were finally released when a sergeant realized who they were and ''apologized.'' The State Police will not comment, even though its Internal Affairs Department has finished its investigation. A police spokesman, Lieut. Joseph B. Kobus, said that the report would be discussed only by Attorney General Irwin Kimmelman, who is reviewing its findings.

TRENTON ONE of the big stories in Tuesday's Democratic primary election will be the performance, or lack of it, of the Hudson County Democratic organization. No one says that the machines run by Mayors Frank Hague or John V. Kenny are still around, but sometimes nostalgia tends to blur reality for those who have inherited what remains of political clout in Hudson. The old bosses had the payroll army and knew how to make much of the electorate feel that their continued well-being depended on how they voted. For example, in the 1934 Democratic primary for Governor, Mr. Hague backed William Dill and then delivered 107,000 votes for him (of the 110,000 cast in the county). In the general election, the Democrat lost to Harold G. Hoffman, and many people accused Mr. Hague of pulling the rug out from under Mr. Dill's feet.

White Plains, whose ''Platinum Mile'' has become a prestige location for Fortune 500 corporations, now has another amenity befitting its image as a corporate center - a luxury, all-suite hotel whose pristine white concrete terraces slant up the northern slope of the city's core. The 137-suite La Reserve, which opens officially on June 17, is designed to offer visiting corporate executives or transferred corporate families the homelike features of a living room, bedroom and a small kitchen.

KEARNY SOME people say that when Msgr. Robert P. Egan left New Jersey Boystown here, after being its director for 26 years, an era ended. The popular priest, they say, was Boystown. Father Egan has been silent since that Christmas Eve a year and a half ago, when the word spread through the chapel at Boystown that he was being transferred. The townspeople, who attend mass there, wept in the pews, it was said, and Father Egan, who was celebrating the mass, looked solemn but did not comment. Although many took to the streets with signs and petitions protesting the transfer, Father Egan said nothing. Former residents of and teachers and volunteers at the home for homeless and troubled boys formed a committee to work for the priest's reinstatement. They telephoned reporters, called news conferences and sent petitions with 10,000 signatures to Pope John Paul II in Rome.

President Reagan's advisers met early today to discuss the Middle East as apprehension grew that Israeli forces were mobilizing for a possible invasion of southern Lebanon. Secretary of State Alexander M. Haig Jr. said on Saturday that the United States considered the Israeli bombings of Lebanon ''a very serious turn of events'' and was working to restore the cease-fire. Early today, an Administration official said, ''The situation does not look good at all.''

A300-acre strip of land in Rye, with three historic houses, a nature preserve, an old cemetery and a possible prehistoric Indian encampment, has passed the first hurdle toward becoming a historic site. It has been approved by the State Preservation Office and sent to the National Landmarks Commission in Washington. But landmark status will not save the houses or the land, according to preservationists. A $10,000 study released last week said that some practical use must be found for the huge old mansions, two of which are owned by the city of Rye, because all are too big to be used as homes and so expensive to maintain that they are deteriorating. Local preservationists, who contributed to the cost of the study, agreed on the need for new uses.