Then she was born with magic, but really bad at making use of it. So she stole magic stuff in the hope it helps her to train her abilities to a useful level. It may even be stuff that's completely useless to her, so she later sells it for cash or trades it for teaching lessons.
I want to go for really basic stuff. Nothing like throwing fire or shoting lightning, maybe a simple charged up punch to get a short opportunity to escape or draw a weapon. But dealing with spirits or divination and such is right out of the question. I don't want to go all warrior/rogue/mage with my first character.