Everything you need to understand or teach In the Hand of the Goddess by Tamora Pierce.
This is the second book in the Song of the Lioness series centered around Alanna of Trebond.
Alanna of Trebond is disguised as a boy so that she can train to become a warrior for the kingdom of Tortall. Alanna's dream is to become a Knight of the Realm and earn her shield. Alanna is 15 when the story begins and is 18 when it ends. Alanna is the squire to Prince Jonathan...