What was going on when I was born?

The Reagan Administration, in an effort to reduce welfare cheating, is proposing the creation of a data bank that would identify the estimated 25 million people on public assistance in a single national list for the first time. A proposed National Recipient Information System, sent to Congress in the last week, would include such data as a person's name, age, address, Social Security number and ''benefit status.'' The information would be made available ''on request'' by the Department of Health and Human Services to Federal, state or local agencies. According to the proposal, the data bank ''will assist in detecting and preventing fraud, abuse and waste and in maintaining the integrity of public assistance programs.''

The New York City Board of Estimate agreed yesterday to obtain the required appraisals for a new land-exchange proposal that could resolve the longstanding controversy over the parks in the Tudor City apartment complex. Under the new proposal by the City Planning Commission, two parks in the Tudor City complex at 42d Street and First Avenue in Manhattan would become public parks. In return, city-owned property at 51st Street and First Avenue would go to the Helmsley real-estate interests.

EW YORK'S sacred music coexists with its lavishly publicized secular concert life, yet remains unnoticed by most people. The reason is partly the wordliness of our time and partly that most people who listen to music in a church do so in their own churches, and don't wander in search of esthetic experiences in the same way that secular concertgoers routinely do. But twice a year, during the great Christian holiday seasons of Easter and Christmas, the sheer quantity of church music grows so abundant that it almost demands to be heard by music lovers at large. This weekend the Easter season begins the 10-day period from the Friday before Palm Sunday through Easter Sunday. And as usual, the city will be full of music meant originally to enlarge upon the Christian experience through sound, but now so central to Western culture that it can be enjoyed by anyone, Christian and non-Christian, faithful and casual, as an esthetic experience. It would overstate the case, however, to imply that there is a complete separation between sacred and secular music, or between the religious and the esthetic experience. In the 19th century, for instance, esthetes argued that music's spiritualty itself suggested the religious experience. Institutionally, the overlap between the sacred and secular musical worlds is everywhere apparent this weekend. Well-known conductors and choirmasters, such as Richard Westenburg and Johannes Somary, got their starts in sacred music or

''For me one of the worst things would be if I woke up one day and said to people, 'I think apartheid is not so bad.'

World oil conditions have returned to the buyer's market that existed before the Iran-Iraq war broke out last September, oil analysts say. Three producer countries have cut prices on certain types of oil, ''spot'' market prices have slipped more than $3 a barrel since Jan.1 and supplies are so ample that talk is growing of further reductions amid a crude oil glut. According to industry sources, Venezuela has decided to decrease the price of No.2 heating oil by about $1.68 a barrel and No.6 fuel oil by about $1.80, effective today. Although price weakness is normal for these fuels after winter ends, the cuts are regarded as reflecting unusually soft market conditions.

The Republican-dominated Senate Budget Committee tonight rejected the austere budget that it had drafted for the fiscal year 1982, creating a delay that Reagan Administration officials feared could halt the budget-cutting momentum. The rejection, by a 12-to-8 vote, occurred because three conservative Republicans who opposed projected deficits totaling $110 billion through 1984 joined with the Democrats who opposed the Administration's tax plan and some cuts in social programs. The Senate resolution proposed $704.1 billion in spending and projected a deficit of $53.8 billion, while the Administration had proposed a budget of $695.3 billion and a deficit of $45 billion. The committee's spending and deficit figures are higher because it used somewhat different economic information in calculating the cost of the Administration's package. House Panel Backs Its Budget Later tonight, the House Budget Committee, which is controlled by Democrats, approved a $714.5 billion budget with a $25.6 billion deficitThe vote was 17 to 13, with only one Democrat, Representative Phil Gramm of Texas, joining the Republicans in opposition to the measure. It included 75 percent of President Reagan's proposed budget cuts.