I think about this book so often but cannot for the life of me find it – it was about a girl from a poor family, maybe in Russia, who leaves home to join a serious ballet or some kind of dance company. Her mother was heavily referenced in the beginning when she was pursuing the opportunity, I think maybe her mom was opposed to her going or pessimistic that it would work out? Then the book focused a lot on the “green room” the girls in the company had to entertain men in as part of the gig which the main character spent a lot of time discussing her uncomfortableness about.
Lost Classics of Teen Lit: Name That Book! 