Here is a link to a Linda Silverman article about gifted girls. It's old but it's short enough that you might get the teacher to look at it. I think that it still is relevant:
http://www.jeffcogifted.org/images/jagc/pdfs/where_have_all_the_girls_gone.pdf
It talks about gifted girls' ability to be chameleons, able to fit in and seem fine, and the downside to this.

Here is a sample:

We know that gifted girls fit in by pretending to be less capable than they really are, and that this habit pattern often becomes a self-fulfilling prophecy (Borland, 1986). If elementary school work is too easy, girls are unprepared to meet the challenges of advanced coursework later on, avoid more difficult courses, which unnecessarily limits their career choices, and come to believe that they really aren't smart (Dweck 1986).