Methinks there's something shady that her parents are keeping hidden from her. That, and her medications that she doesn't even know why she's taking, all lead up to mayyybe suppression of a large power amount she unknowingly has - that's maybe why she struggles with hiding her crystal thingy even though it's something she should've been able to do by now.
Well, these speculations might be more obvious than not, but what's more interesting is why it might be hidden and what would it cause to happen if her powers were revealed.