I Wanna Be Your Girl, Vol. 1 (Kanojo ni Naritai Kimi to Boku, #1)

Hime and Akira have been friends since they were little kids. At age 12, Akira reveals to Hime that Akira is actually a girl at heart. She begins to dress like a girl and is bullied and harassed at school. Hime will not stand for it, and begins to dress as a boy in support of the friend she loves. Of course, this means their troubles at school are only just beginning.