Continuity mistake: When Lola's Mother finally acknowledges her as being Lola, she is seen walking backward towards a green door. The camera moves to Lola, then back to the Mother where there are now two backstage people standing behind her, in front of the green door.
Continuity mistake: When the kids are auditioning for parts in the play, the kids in the seats during Lola's audition change positions throughout different shots. (00:15:55 - 00:19:30)
Continuity mistake: Lola's necklace changes between shots from a choker to a long necklace several times throughout the movie.
Continuity mistake: When Lindsay Lohan searches through literally a pile of clothes her blonde friend suddenly feels guilty about lying to her parents. During the following discussion on the bed the camera changes angle frequently. Although at the lower end of the scale of continuity error, you can see that the facial expressions of the blonde girl differ frequently from shot to shot, not in line with the continuity of the scene. (00:32:45 - 00:33:20)
Answer: My only guess is that she had to make sure the dress fit before the play, or adjustments had to be made on the dress so it would fit her.