Dealing with Dragons / Patricia C. Wrede 212 p. 1st in series ; fairy tale

Princess Cimorene takes the non-traditional princess path.  She wants to do things.  She is bored so she takes Latin lessons, wizard lessons, and when talk turns to marriage, she runs away to work for the dragon Kazul.   There she uses her many skills and uncovers a plot by the wizards to steal the dragon's kingdom.