Try to google on "blend in" of gifted children and you can read about what she is really going through. Here is an informative link and I am sure that there are many more useful links out there: http://sengifted.org/the-me-behind-...ed-students-and-the-search-for-identity/

I can share with you our situation and how we handled it: my DS went into public K being able to read, write, add, subtract etc and he was very verbal and had thrived in an environment that encouraged him until that point. In public K, he was put into an advanced classroom with 1st graders and he was still standing out in that room because of his abilities. He made no friends because other kids could not relate to him. Over a period of months, he began mimicking the popular kids in his class in speech, mannerism etc in order to blend in. Whereas before he used to talk in complete sentences with accurate grammar and complex vocabulary, he deliberately started dumbing down (e.g. I "runned" during recess", "I "writed" my homework" etc) - it looked like he was not putting up his hand to answer teacher's questions in class as well (I was in the room and observed it).
He later said that all the kids around him talked like that and he stood out by talking "differently" and that they were "mad" at him when he corrected their grammar. He also said that he was the only person who put up his hand in class all the time and that he got labeled a "show off" which hurt his feelings.
We realized that peer group was very important to my social kid and that he was becoming a vastly different person because of trying to fit in. We have moved him to a school where there are kids who are more accomplished and have higher abilities than him smile He will not be considered a show off in class any more because he is not always the first to come up with answers now. There is healthy competition in the classroom. Until we found the correct fit, it was a hard journey that involved many school changes and family instability due to relocating for schools etc.