It’s the time of year when young dancers at the New York-based School of American Ballet find out whether they have been chosen to serve as apprentice members of New York City Ballet, and the competition is fierce, with good reason. “Every year 6 to 10 advanced dancers from the school join the company as apprentices, enjoying essentially a trial run. Almost all stay on as permanent members. In fact, the ballet company draws an overwhelming number of its dancers from its school — 90 of the current 97.”