Not a full-grade skip, but our child will be in seventh grade in three classes (basically half the school day) assuming he stays in the same school this fall. He will turn 10 just before school starts. He's been in a two-grade skip in those classes for about two school years. It's worked very well as far as getting along with the older children in class. It was a bit harder while he learned to manage the work requirements but he did do so. He can't imagine being in a lower grade for those classes.

I'd take comfort in the fact that your child is excited about this additional skip. Perhaps talking with her and the school about how to test the skip out for a trial period and what will determine for all if it is a good thing would help?