An ordinary life for Vanessa Williams, the new Miss America and the first black woman to win the title in its 63-year history, ended early yesterday morning when she accepted all the glories, responsibilities and headaches.

First, Williams, a 20-year-old musical theater major at Syracuse University, etched her place in history by breaking one of the country's oldest remaining racial barriers, the beauty pageant, that plucks one woman out of obscurity and makes her a symbol of the country's youth, beauty and talent. Miss New Jersey, Suzette Charles, 20, who is also black, was first runner-up to Williams, who was Miss New York.

And, in another break with custom, Williams was outspoken on political issues, race and beauty contests. She described herself as a political independent, oppoosed to the legalization of marijuana and favoring the passage of the Equal Rights Amendment. She said the Russians couldn't be trusted, according to one report. On abortion, Williams said, "I think it's a right women should have. It should be there for women to use but I don't think everyone should use it."

Early yesterday morning, the winner seemed to be getting testy about the racial symbolism. "At times I get annoyed because people and the press aren't focusing on me as a person and are focusing on my being black," said Williams at a news conference. "I've made some waves and I'm ready to handle that. People aren't used to dealing with change, but I think it has to happen."

But her reign will undoubtedly bring great attention. After her traditional walk down the 134-foot runway, President Reagan called to say, "Your selection is not only a wonderful thing for you. It's a wonderful thing for our nation." He invited her to the White House. Soon afterward, Benjamin Hooks, executive director of the NAACP, was comparing her to Jackie Robinson.

Upon hearing the news of her win, neighbors in her hometown of Millwood, N.Y., a suburb of 2,500 in Westchester County, set off fireworks and popped champagne.

And after only two hours of sleep, Williams was posing for photographers; running long strides on the beach at Atlantic City, smiling warmly with the boardwalk in the background -- all time-honored duties for the contest winner.

"I've never felt like a beauty queen and I don't think I ever will, because that's a stereotype I don't agree with," she said. But she has all the stunning qualifications, with wide, green eyes and a full mouth boldly branded on a sunny, oblong face. Her brown shoulder-length hair falls in loose waves highlighted with gold. For the record Williams is 5-foot-6 and weighs 110 pounds. And some blacks will probably use her looks, which fit the old Miss America standard, of fair skin and straight hair, as a criticism of her victory.

By early afternoon, the wire services were chattering about her support of legalized abortion and calling her "America's new sweetheart."

By mid-afternoon yesterday, she was incommunicado, somewhere between Atlantic City and New York's Plaza Hotel, where she is scheduled to meet the press today for about the third time in two days.

Beauty pageants, particularly the Miss America contest, have long been holdouts to racial integration. The Miss America contest, which originated in 1921, officially barred minority competition until the late 1950s. Criticism by blacks of the contest as "lily white" was heard frequently. Until the first black competed in 1970, blacks had only appeared on stage playing slaves in a 1922 production number. This year there was four black contestants and one Hispanic.

Yesterday, Williams described herself as an individualist on racial issues. "Just because I'm black doesn't mean I'm going to support every black position," she said. She supports a national holiday for the Rev. Martin Luther King Jr.'s birthday. She also said she expected to be invited to conferences, like that of the National Urban League, that previously weren't interested in the Miss America titleholder.

In the week-long Miss America pageant, Williams won two preliminary competitions, swimsuit and talent. From the first time last week that she sang "Happy Days Are Here Again," in the style of Barbara Streisand, it was obvious she was special. "I'm a stylistic singer, like Lena Horne," Williams said at the time. "I don't have the legitimate voice, like an operatic singer, or a jazz singer who slides in and out of every note."

One reporter who attended Friday and Saturday's competition described it this way: "On Friday night when she won the talent competition, she just took command of the stage. She was dynamic. Yesterday, she said she chose the song because it is optimistic and she is an optimistic person."

Williams reportedly had a sense of humor about the attention being paid to race. "She said she realized it was a big deal and that she had become used to that during the week," said the reporter. "She said for the first couple of days the reporters and photographers were asking for the black contestants. So it had become a joke by the end of the week, and when they asked her to pose, she would say, "Don't you want Maryland, North Carolina and New Jersey too?""

Williams was born in Tarrytown, N.Y., and lived in the Bronx for a year. Since then she has lived in Milltown, where both her parents, Milton and Helen, teach music in public schools. She has a brother, Chris, 15.

While at Horace Greeley High School, she entered her first pageant, sponsored by the Masons. She finished fourth nationally. She has worked as a model and studied acting, French horn, piano and dancing. She has also been a presidential scholar finalist in drama.

Her interest in the contest goes back only six months. According to one report, she was encouraged to enter the Miss Syracuse contest by its director, Victoria Longley, who saw her on the cover of a local entertainment newspaper.

"I am very grateful that she discovered me for this," Williams said.

After that she became the first black to win the Miss New York title. "I had no idea I would get this far in such a short time," she said.