It seems that she can do the work but the trend is that she is not motivated to do her best. That would be the problem I would focus on and try and solve.
Yes, that's exactly what is bothering me. She is abusing the privilege she has been given and she wants the positive accolades that come with being accelerated, but she doesn't want to work for it. She just wants everything handed to her. It is a personality characteristic that is not at all positive and which we have had a really hard time combatting. Putting her in non-accelerated classes hasn't worked either b/c it reinforces in her mind that she is stupid and her achievement scores sink. She feels better about herself and gets higher achievement scores when in advanced classes, but she is unwilling to do the work.
