Athena the Brain by Joan Holub

Athena has always been above average. She has never quite fit in at Triton Junior High, but who would've guessed that Athena is actually a goddess? Principal Zeus's daughter, to be exact.
When she's summoned to Mount Olympus Academy, Athena thinks she might actually fit in for the first time in her life. But in some ways, school on Mount Olympus is not that different from down on Earth, and Athena is going to have to deal with the baddest mean girl in history: Medusa! From Goodreads

This is a sweet, cute easy read for young middle grade children. The Gods and Goddesses of Greek mythology are around the age of 12.

This book qualifies for:
Goodreads 2013 Reading Challenge
Serious Readers 2013
Tower Teams Read 2013-2
2013 Ebook Challenge
2013 Mythology Challenge
2013 1st In A Series Challenge