I just want to say congrats on being the kind of parent your daughter can honestly confide in!

I know it currently feels like academic achievement is everything, because that's really the only measure of achievement you have for a child that age, but she's only 11 and as others have noted, grades start to matter in high school. This isn't really cause for alarm.

I was that overachieving girl when I was her age…if all she does is study it can lead to burnout. That said, it sounds like she's balanced and popular so I wonder if this has more to do with her hitting an awkward developmental age for girls. It's one thing to want more balance and social time but it's another if she has those things and she's sabotaging herself. Perhaps she's starting to struggle with the idea of what it means to be a woman and it could be that her understanding of social norms for femininity doesn't include being smarter than everyone else?

You say you're at a University…does she have a favorite class or a career/field she finds exciting? Maybe you can introduce her to some smart, hip female role models from the University?