One, Two, Three is an easy read-- that is if you know nothing about ballet. There is a certain reverence dancers have toward their art and they would never use ballet terms as allegory. I think the author was trying at add a bit of color, but in my opinion, this was a flawed move.
Still, though, she did a great job portraying the alcoholic mother and the strife Natalia went through. While this is meant also to be a romance, I would view it more as a coming of age story.