The Wee Free Men: Terry Pratchett

The first book in the Tiffany Aching series - five Discworld novels from master-storyteller Terry Pratchett.
Tiffany wants to be a witch when she grows up.
A proper one, with a pointy hat. And flying, she`s always dreamed of flying (though it`s cold up there, you have to wear really thick pants, two layers).
But she`s worried Tiffany isn`t a very `witchy` name. And a witch has always protected Tiffany`s land, to stop the nightmares getting through.
Now the nightmares have taken her brother, and it`s up to her to get him back.
With a horde of unruly fairies at her disposal, Tiffany is not alone. And she is the twentieth granddaughter of her Granny Aching: shepherdess extraordinaire, and protector of the land.
Tiffany Aching. Now there`s a rather good name for a witch.