Karen Cushman 
Grayling’s Song [EPUB ebook] 

Grayling doesnt want to be a hero, but to save her mother from a dark enchantment, she seeks out the few second-string magic makers who havent been immobilized by the spell and goes off in search of her mothers grimoire, or book of magic. Obstacles both natural and supernatural block their way, and friction within the group delays the journey. Surprising herself, Grayling finds the strength and decisiveness to move the group forward and reach her goal. Eccentric witches and wizards plus a shape-shifting mouse provide moments of high comedy, as do odd practices that date back to the Middle Ages, such as divination with cheese.