What was going on when I was born?

The National Mediation Board, in an unexpected move, announced yesterday that it would intervene in the labor dispute involving the commuter rail lines to New York City's northern suburbs. The board said it would also intervene in disputes in New Jersey and Pennsylvania. All three disputes stemmed from the scheduled takeovers by local authorities of commuter services from Conrail on Saturday. Negotiations with rail unions have been at a critical stage, leading to fears of a strike. But the board's action in Washington means that working conditions and pay scales now in effect would remain - contrary to changes sought by the Metropolitan Transportation Authority - thereby reducing the prospects of a walkout on New Year's Day.

Governor-elect Mario M. Cuomo said yesterday that he would ask the Legislature to enact changes in the method of selecting judges for the state's highest court. The proposed modifications are designed to diversify the pool of candidates for seats on the New York Court of Appeals, as well as to give the Governor a longer list of people to choose from. Earlier this month, a special nominating commission forwarded to Mr. Cuomo the names of four candidates for the court seat now held by Judge Domenick L. Gabrielli, who is retiring tomorrow. None of them were women or had extensive criminal-justice experience, two specifications that Mr. Cuomo had suggested, and he asked the panel for more names. The panel responded that it could not legally do so.

The nation's merchandise trade deficit narrowed to $4.1 billion in November, from $5.3 billion in October, the Government reported today. But for all of 1982, the deficit seems certain to exceed the 1978 record of $42.4 billion. Saying that it was ''not unreasonable'' to assume that December's deficit would be $5 billion or more, David Lund, a Commerce Department analyst, declared: ''There will be a record deficit this year.'' Last year's trade deficit was $39.7 billion, and that for the first 11 months of this year was $39.1 billion.

''I intend to go right on living. That may come as a disappointment to some.''

The executive committee of the union representing Legal Aid Society lawyers in New York City voted yesterday to recommend acceptance of a tentative agreement to end a 10-week strike. The new two-year contract would run until July 1984 and provide for wage increases of 6 percent in the first year and 5.2 percent in the second. Union members are scheduled to vote on the proposal at 10 A.M. today. If it passes, the lawyers could be back at work on Monday, according to Gary Sloman, a spokesman for the union, the Association of Legal Aid Attorneys.

The Southern New England Telephone Company, 23 percent owned by the American Telephone and Telegraph Company, said it would enter the telecommunications equipment business outside of its home state of Connecticut, a move that will make it the first Bell System company to compete against A.T.& T. in equipment sales. Southern New England's plans came to light yesterday after the scheduling of a news conference Jan. 4 in Hartford to announce the formation of a new corporate division to handle equipment sales. Company officials and industry consultants said they expected the division to be called Sonecor Systems.

Money, according to the master of ceremonies in the musical ''Cabaret,'' is what makes the world go round. Milton Friedman, who has a Nobel Memorial Prize in Economic Science, agrees, at least up to a point. The bandits who stole $10 million (give or take a few pennies) from the Sentry Armored Car Courier Company in the Bronx a few weeks ago presumably enjoyed somewhat more of it this Christmas than last. And Robert H. Reid, who is one of the best-known Fed-watchers on Wall Street, makes a nice living predicting how ''the money supply,'' whatever that is, will behave from week to week. Plainly, money is interesting from almost any vantage. But new Federal rules, which this month lifted the interest-rate ceilings on money market accounts at banks and savings institutions and next month will do the same thing for individual checking accounts, have also created new uncertainties about whether money can be controlled or defined.

The Federal Reserve Board gave notice today that it would review the Dreyfus Corporation's acquisition of a small New Jersey Bank, despite Dreyfus's contention that it has taken Lincoln State of East Orange out of the Fed's jurisdiction. William Wiles, secretary of the Fed, said in a letter to the legal counsel of Dreyfus, a major mutual fund operator, that the transaction ''will be brought to the attention of the board in order to determine what further action is necessary.'' Commercial Lending Stopped In acquiring Lincoln State on Monday, Dreyfus terminated the bank's commercial lending activities and divested itself of its commercial loan portfolio. As a result, Dreyfus maintains, Lincoln State is no longer technically a bank, as defined by the Bank Holding Company Act, and thus is not subject to the authority of the Fed. The act, which prohibits the common ownership of banking and commercial enterprises, defines a bank as an institution that accepts deposits and makes commercial loans.

Hugh L. Carey bade farewell to the Capitol today with a final slap at the Legislature, some advice for the press and the disclosure of one last bit of self-described political ''mischief.'' Governor Carey, who decided earlier this year not to seek reelection, said he was moving on to make some money and be with his family, though he also hoped to speak out on such issues as the economy and nuclear disarmament. ''I intend to go right on living,'' he said. ''That may come as a disappointment to some.''

After a day of sporadic vandalism, car-burning and stone-throwing, a poor, largely black neighborhood north of downtown was tonight declared ''a restricted area'' by Miami's City Manager. The violence began Tuesday night, when several hundred people took part in a disturbance that followed the shooting of a young man by a Miami police officer. The young man, Novell Johnson Jr., died tonight in Jackson Memorial Hospital. A youth who the police said was trying to loot a warehouse was shot to death, and several injuries were reported. Local and Federal officials announced today that they would investigate the incidents.

With the New Year weekend approaching and not a flake of snow on the ground, Maurice Dennis decided it was time to do his dance. Mr. Dennis, a 74-year-old Abenaki Indian and a lifelong resident of Old Forge, N.Y., donned headdress, mukluks and other traditional garb and led a large crowd to the Christmas tree in the center of the community, whose economy depends on an annual influx of skiers and snowmobilers, where he called on the Great Spirit. ''I did a snow dance,'' he said. ''I played my tom-tom and sang ancient songs I learned from my father. ''Unfortunately, it only rained a little. But I've agreed to try again. It's important for the town. And I happen to be a skier myself, as a matter of fact.''

I have nothing against New Year's Eve. I am as accessible as anyone else to the collective giddiness that will take hold of us tomorrow at nightfall and grow more vertiginous as the evening proceeds. New Year's Eve is an occasion unlike any other. At the stroke of midnight tomorrow a new year will come down the pike. Why should not a new life come down with it, and a new self as well? What was ever lost by hoping? But as a veteran of many a long New Year's Eve, I have an opinion or two to put forward about this particular occasion. New Year means transformation the world over. When the big number changes we feel shaken, as if by a benign and very small earthquake. And that earthquake may have magic powers. Why should not every frog become a prince and every maid a princess? Nothing is impossible. If the New Jersey swamplands were to turn into the Garden of Eden on New Year's Eve we should not be the least bit surprised.