I'd gently steer her towards learning about nature, finding her place in the world, and maybe encourage her by buying her a teen witch book. I'd also talk to her about living a good life, being kind, and generally all the things which you probably do anyway.
You might try doing little protection rituals with her, such as blessing your home and car, or manifesting parking spaces. How about growing herbs?
There are also some lovely tarot decks available, if she has an interest in that sort of thing.