Millicent Min, Girl Genius (the Millicent Min Trilogy, Book 1)

Millicent Min is having a bad summer. Her fellow high school students hate her for setting the curve. Her fellow 11-year-olds hate her for going to high school. And her mother has arranged for her to tutor Stanford Wong, the poster boy for Chinese geekdom. But then Millie meets Emily. Emily doesn't know Millicent's IQ score. She actually thinks Millie is cool. And if Millie can hide her awards, ignore her grandmother's advice, swear her parents to silence, blackmail Stanford, and keep all her lies straight, she just might make her first friend. What's it going to take? Sheer genius.