The Magic of Inherian: The Mage of Monrovia, Book 2

Mexia has already done much more than most school- trained mages when she and her companions had gone in search of the scepter of salvation. But now one of the apprentices of the evil wizard they had destroyed, has stolen his spell book and plans to take up where he had left off, and she has to try and stop him.

Mexia believes the only way for her to defeat the mage is to become school trained like he was with the eventual goal of becoming a high wizard--the first of her kind in Inherian. But the current headmaster denies her entrance because she's a woman. Though if she can get the former headmaster's recommendation, she may attend.

And that's the beginning of the trouble.

First, there's the wizard.
Then, the immovable headmaster.
And then, the circle of misfortunes.
It all goes downhill from there...