Witch in Hiding (#1 in the Witches Trilogy)...
Vinni is in trouble. Not just because she's failing maths or playing second fiddle to a perfect younger sister or pretending not to miss her absent father, but also because she's just found out she's a bona fide witch, and someone is out to kill her before her thirteenth birthday.
Her mother isn't talking, but other people are: apparently, it's not a coincidence she was enrolled in her school. Everywhere she turns, another door in the magical community is opened to her; her best friends are magical creatures, disguised as awkward preteens, but unfortunately, so are her enemies.
Link to sequel: http://www.wattpad.com/story/1714493-witches-in-training-2-in-the-witches-trilogy
Link to book 3: http://www.wattpad.com/story/1825635-witch-missing-3-in-the-witches-trilogy