Although my son is younger - only 5, we were seeing a very disturbing trend of apathy and general "blah-ness" for anything and everything aside from a very few random activities. He decided he could no longer do maths, could not read, could not figure out anything on his own.
I took him out of his gifted school even though they offered us a skip - he has confused the idea of learning with the concept of being at school. He believes that he will never learn anything new at school.
He has been home nearly 2 months now and we are still de-schooling. Although we have a specific outline to our day, he gets to choose what he does every day. At first it was literally only going for walks, jumping on the trampoline, playing on the PC and watching TV. Only this past week has he tried to set up a few experiments, started reading of his own accord again and started seeking out maths again. ITs still all at a level he was comfortable with nearly 18 months ago, but its the first sign of HIM we have seen in ages.
The point to my rambling - why not let her do the powerpoint, the dancing etc for a while? It could help her heal the underachievement, it will make everyone happier, and I am sure that once she feels fulfilled again she will of her own volition seek out academic work again. And then it will be what she is interested in, at her own level. This will also ensure that SHE oversees her learning as it is what interests her.
Buying a set curriculum at a specific grade level may only reinforce pre-concieved ideas based on another adult's ideas/expectations. There are so many resources available, that I'd suggest at the very least you allow her to select what she would like to study and get only the materials to support those choices at those levels. You can set guidelines and ground rules in terms of neatness etc, but I am sure that you can then build in everything you think she may need into what she really wants to do.
Just my ideas and ramblings. I hope that the transition brings peace of mind to both of you
