Keep modeling of course, and it could be in part due to a development milestone... but also consider the fact of any stress/anxiety she's experienced at school or being out of sync with her peers is the root of the problem (the onset of this behavior). Do you think any of the kids she interacts with are her "true intellectual peers" or who she's on the same wavelength with? (sorry my grammar there is pretty bad)

Anyway just a thought...see if there is something bugging her