What was going on when I was born?

The fire that killed eight young people at the Six Flags Great Adventure amusement park last week was started by a youth who lit a lighter to find his way, investigators reported today. The investigators said the lighter ignited a large foam-rubber pad in a room that was dark because of a malfunctioning strobe light. The fire, fanned by air-conditioners, then swept through the eight trailers that made up one side of the attraction, the Haunted Castle. The youth who ignited the fire was believed to be 14 years old, and was not believed to be among the victims. The investigating panel reported that the Haunted Castle violated up to a dozen state regulations.

The economy raced ahead at an 8.8 percent annual rate in the first quarter, even faster than previously estimated, the Commerce Department reported today. The new calculation of the gain in the gross national product, the national output of goods and services, compared with earlier estimates of 8.3 percent and 7.2 percent.also said after-tax corporate profits rose in the March quarter after a dip late in 1983. The new figures were regarded as further indications that the 18-month- old recovery, which many economists say is threatened by very high interest rates, will endure well into 1985. But in what is becoming an increasingly frequent response to apparent good news about economic growth, stock prices fell broadly today. Traders said they feared that the continued brisk pace of expansion would keep interest rates high and could lead to an abrupt downturn in the economy.

The unprecedented $7.5 billion emergency aid package extended by Government agencies and private banks to insure the survival of the Continental Illinois National Bank and Trust Company has apparently halted the run on the giant Chicago bank and calmed world financial markets. ''It's been quiet today and the action seemed to stem the outflow,'' a Continental spokesman said yesterday. The spokesman also said the rescue package, the largest such package ever assembled by the Government, was used yesterday by the bank, but he declined to elaborate on the amounts. The package included $2 billion in new capital for the bank and a $5.5 billion line of credit from 28 banks. In addition, the Federal Reserve, the nation's central bank, said it would provide funds to meet daily cash requirements beyond the $7.5 billion commitment.

The Food and Drug Administration today approved the nonprescription sale of a pain reliever that will compete with aspirin and the relatively new drug acetaminophen, which is best known by such brand names as Tylenol and Datril. Both the drug agency and the manufacturers say the newly approved drug, ibuprofen, offers relief from both pain and inflammation, like aspirin, but is less likely to irritate the stomach. They say it presents less risk of harmful overdose than acetaminophen, which does not work against inflammation. And it is described as providing relief for menstrual cramps.

Physicians conducting a full medical examination of President Reagan today discovered and partly removed a small polyp from Mr. Reagan's colon. Hours later they determined that it was benign, the White House said tonight. Larry Speakes, the White House spokesman, said the existence of the polyp was ''a normal development in the intestinal tract'' and caused ''no undue anxiety'' in the President or his aides even before it was diagnosed as benign late in the afternoon. In every other respect, Mr. Speakes asserted, physicians conducting the medical examination of Mr. Reagan at the National Naval Medical Center in Bethesda, Md., reported that he was in good health.

When the oil boom waned two years ago, there were fears that the economic and population boom in Lafayette, a headquarters for offshore drilling, would wane as well. But Lafayette has remained one of the nation's fastest-growing metropolitan areas. New homes and office buildings rise from oak forests and rice fields. A diversified economy has helped the area of 226,000 people retain Lafayette's reputation as a place of opportunity. The continued growth of Lafayette and other oil-producing areas is one of the significant population changes across the United States that followed the national recession of the 1980's, the most severe since the 1930's, and other economic upheavals.

The Reagan Administration today reaffirmed its determination to try to limit the war between Iran and Iraq. The statement came amid growing international alarm over attacks on oil shipping in the Persian Gulf and a new assertion by Iraq that its warplanes had damaged more vessels there. The spokesman for the State Department, John Hughes, said the United States was ''prepared to work with others, particularly the states of the region, in common efforts to contain the effects of this tragic war,'' but sought to minimize any appearance of a military crisis. 3 Tankers Hit This Week Iraq said today that its planes had attacked and damaged two large ships in the Persian Gulf, but Pentagon officials said they could not confirm the report. At least 17 ships have reportedly been attacked in recent months by Iraqi or Iranian warplanes. One Saudi tanker and two from Kuwait were reportedly hit by Iran this week.

A Sakharov letter is on page 4. WASHINGTON, May 18 - State Department officials said today that the wife of Andrei D. Sakharov gave American Embassy officials in Moscow letters last month in which he disclosed plans for a hunger strike and asked that his wife be given temporary refuge in the embassy. But the officials said that Yelena G. Bonner, Dr. Sakharov's wife, had not discussed the hunger strike, which Dr. Sakharov began May 2, or the appeal for her to stay in the embassy. The State Department said the embassy did not know of the plans until after Miss Bonner had left for Gorky, where her husband has been exiled since 1980.

Armed policemen in combat gear occupied the central bank today while employees remained on strike to hamper the introduction of austerity measures aimed at getting a loan for Bolivia from the International Monetary Fund.

The biggest business in this tiny country is the khat trade. Khat, a narcotic leaf that produces mild stimulation, is Djibouti's unofficial national plant, the much loved legal drug of inhabitants of the Horn of Africa. Each day 8 to 10 tons of the stuff are flown from Ethiopia to Djibouti by Air Djibouti or Ethiopian Airlines in the cargo hold and economy sections of the planes. No passenger is more eagerly awaited. At 1 P.M. some 300 drivers of green and black official taxis, known as the Sultans of Khat, assemble at the airport to carry the plane's precious cargo to customers throughout the country. The plant must be chewed while it is fresh or it loses potency.

A Government spokesman said today that Greece had expelled a United States diplomat. The spokesman affirmed a published report here that the envoy was an agent of the Central Intelligence Agency. The Government spokesman, Dimitris Maroudas, said the contents of the report, in a Greek satirical newspaper, were accurate, but would not elaborate. The newspaper report appeared earlier today, shortly before the Government announcement.

The executive committee of the International Olympic Committee met here with a Soviet delegation today in an apparent effort to reverse Moscow's decision to stay away from the Games in Los Angeles. The effort was apparently unsuccessful. Later the committee said it deplored the decision of the Soviet Union and nine other nations to pull out of the Games. They said the action would greatly damage the Olympic movement.