Revealing mistake: In the final dance audition it is obvious that Beals has a stunt double during some of the takes, as the face is different and the double is wearing blueish eyeliner or shadow and reddish lipcolor.
Continuity mistake: When Alex and Nick enter her place, the layout is quite different from the movie's opener. Which was a large, near empty warehouse. It is now much smaller, and bedazzled with bling, including sparkling mannequins for dress making.
Continuity mistake: In the hallway on the way to gym, only Alex, Tina and the other girl are seen. But, in the workout montage, Jeannie suddenly appears.
Answer: It states early in the film that Alex went to the ballet and was enchanted by it and started her love of dancing. Her girlhood dream was always to be a part of the conservatory and dance the ballet's one day. Her going to the conservatory was to LEARN that building on her knowledge. Besides, normally she wouldn't have gotten an audition with her lack of Point training, but for Nick's intervening.