In the dressing room yesterday afternoon Christopher Boatwright was walking the highwire of pre-performance anxiety with frantic caution, waiting to go on stage in the title role in the Stuttgart Ballet's presentation of "Romeo and Juliet."

"I want to scream when the curtain goes up, 'No, I don't want to do it, let me go!" he said. "Especially when it's something last-minute like this."

It wasn't supposed to dance the role until Saturdays's matinee. But then very little has turned out quite as expected for Christopher Boatwright.

"I was supposed to be the first black president of the United States," he said, nursing a root beer and a Marlboro."But I always wanted to dance."

Dancing was not, of course, what his middle-class family envisioned for him. But at 17, he abandoned their fond dreams for the streets of New York City.

He is 24 now, one of the company's principal soloists, a young man of liquid eyes and velvet features. Now he is ensconced among the stolid burghers of Stuttgart, Germany whose ideas of the middle class and what constitutes the right thing make the quiet family neighborhood in Brooklyn seem a hotbed of hedonism.

He has lived in eight apartments since he came to Stuttgart," he said a little ruefully. "They don't mix."

The citizens of Stuttgart, at least those who have been Boatwright's neighbors, are big on house cleaning and very down on late-night music-priorities Boatwright tends to reverse. They also find the concept of a young black male ballet dancer somewhat astonishing at first.

"The first year was terrible," he said. "I'd walk down the street and little children would say in German, 'Look, mother, a balck man.' They weren't used to it. It wasn't as if people were unfriendly, it's just that when you're considered that different, you get a little paranoid."

He was 18 that year, and had just come to ballet. "I had been a street boy in New York," he said, "working in restaurants and things. I walked by this fine arts workshop in dance that was being given. it was free, so I went."

He later won a scholarship to study with Merce Cunningham, and checked out different ballet schools in New York.

"I wanted the discipline, I needed to learn," he says. "But everywhere I went, they were all hopped up on the competitiveness: who's got the longest leg, the prettiest face? I didn't want to learn how to fight. I didn't want to fight."

He heard about Stuttgart from a dancer with the Dance Theatre of Harlem. "He was black and he had danced with Stuttgart. I figured Germany was a rich country; they could probably give me a scholarship."

Which happened - in roundabout Boatwrightian fashion. He auditioned for a place in the company's school in Stuttgart, was accepted but was too broke at attend until, at the last minute, the John Cranko Foundation came through with a scholarship.

He still feels uneasy in the town of Stuttgart. "You never know if you're doing it right. You never know what the rules are." The buffer between Boatwright and the real world was found in the company itself - large and boisterous and cosmopolitan, speaking a brand of English that often preciptiously lapses into a wide variety of other languages.

"I made it my world," he said. "We only have each other and the theater."

The dancers leave their cloister in force to confront the real world - "bombarding a restaurant of a disco like a big family, as if we were all tied to the same tether. That way, when they look at us and how we're behaving, they just say 'On well, that's just the Stuttgart, that's the way they are.'"

On tour, particularly in London and the States, "We just go crazy." In fact there are times when Boatwright and some of the others act as if they have been let loose in an enormous playground.

After a rehearsal a Swiss member of the company described his latest cultural foray into deepest Washington: "Have you been to this place called the Howard and Johnson?" he asked. "It's fabulous. You have to try their pina coladas."

Boatwright wanted to know how much they cost. The Swiss said $2.50. "Thaths about five marks," said Boatwright. "Not too bad."

Germany is more or less home now, and sentences often end in a German word until the English equivalent is rediscoverd.

His feelings about America are mixed. He misses the casual, uninhibited nature of life as he remembers it, the choices in dress , the friends and the leisure.

But the first trip back to New York City a few years ago left him "stunned. It was a real cultural shock. Nothing seemed right, everything looked dirty."

Seeing his family again was the trial it often is on that first trip back after the newly adult have recreated themselves in their own image. And the New York City dance world was no more attractive.

"It was all the same - all the pretty faces, and long legs, 50,000 little ballerinas and they all look the same and talk the same and they don't even realize it. Did they really choose to be what they are?"

His fierce opposition to the competitive nature of his art colors his attitude toward the future. "I don't think about the future," he insists. "I don't have any plans. I know I should. I'm not a go-getter.

"I've got it and I'll get it , but I'm not aggressive about it. Dancers have such short lives, and most of them spend it worrying about getting to the top. I'd like to savor it as I go through it."

For the time being, the future stretched only as far as the evening, when he would dance the role, although, in the beginning, he said, he "had a tough time relating to classical ballet roles. I always thought of princes as blond and white and very tall."

Now, he says, Romeo is his "most favorite role. It means a lot to me - a three-act ballet and there's no limit to my expression. I think of myself as a Romeo. I like to fall in love a lot. I'll do anything for love. I'll lose my job or . . ."But at that, he stopped. "Well now, I wouldn't."

He was reminded that Romeo had a tragic end. Could he meet a similarly unhappy ending?

"I might. But it wouldn't happen in a crypt.It would probably happen in a basement." CAPTION: Picture, Christopher Boatwright, by Harry Naltchayan-The Washington Post