Janis Roswick, who has the lead, of sorts, in William Richert\'s documentary, \"First Position,\" is an 18-year-old New York girl who hopes to become a dancer. She is pretty, a little plump, not noticeably graceful except when dancing, and resolutely middle class. Her public life is the round of \"classes\" (beginner, advanced beginner, intermediate and upward) that fill the days of any ballet student in this city. Her private life is a happy family outside Manhattan, a shared apartment in town, romantic interests in another student (Daniel Giagni) and an introspective diary in which she keeps account of these important years in her emotional and spiritual development. \"My pink stage is slowly becoming deep cranberry red . . .\" she writes. She isn\'t kidding. Janis has in superabundance the capacity for awe at herself that seems the identifying characteristic of bright young people native to New York City. But \"First Position\" isn\'t about Janis only. It is also about her boyfriend (not really; they\'re both too shy), whose life outside the dance includes training to be a clerk-typist in the National Guard. And it\'s about other students: a clever, ironic man who loses out in Janis\'s affections, and a talented but insecure boy who finally goes home to Florida to become a bagger in a supermarket—after almost succeeding at ballet school in New York. The school itself (the American Ballet Theater School, though its identity isn\'t too important) we know mainly through the qualities of some of its teachers—the vigorous Valentina Pereyaslavec, and Leon Danielian, severely crippled by arthritis, who spends most of the movie in a wheelchair. For an image of personal presence, Danielian\'s taking command over a dance class, even from a wheelchair, will do until something pretty spectacular comes along. From time to time the film cuts to passages from the recent Ballet Theater production of \"Petrushka\"—almost the only formal dancing in the movie. \"Petrushka\" is in costume, but danced in a semi-darkened classroom rather than on stage. Given the ballet and the setting, the effect is chilling and oddly dispirited. This is what we see of success in the film\'s terms. It isn\'t glamour; it\'s more like loneliness and a vague fear. And it is emblematic of what raises \"First Position\" above the level of sensitive slice-of-life documentary—to provide a vision of what lies just beyond, say, the winning self-assertion of Janis\'s diary, the classroom discipline, or Danielian\'s personal bravery. Temporary victories against time, they lead finally to a lovely expression of defeat, and that is how they are understood in this very good movie. \"First Position\" opened this week at the First Avenue Screening Room. The Cast FIRST POSITION, directed and produced by William Richert; director of photography, Gerald V. Cotts; editor, David Hill; released by Roninfilm. At the First Avenue Screening Room, at 61st Street. Running time: 92 minutes. This film has not been classified at this time. WITH Leon Danielian, Janis Roswick, Daniel Giagni, Valentina Pereyaslavec, David Prince, Yurek Lazowsky, Michael Maule, Andrei Kulik, Marlise Rockey, Valentina Vishnevsky and students of the American Ballet Theater School.