Need advice on daughter's interest in Wicca..

[Brett's Honey]

My 13-year old step-daughter, along with her cousins and some of her friends, watches "Charmed" and has developed a lot of interest in Wicca and witchcraft. My husband and I aren't really freaking out, but we don't care for it either. I'm 99% sure it is a phase, considering her age and the TV show that got her interested. We hesitate to make too much of a big deal about it, since sometimes that just makes kids more determined to do whatever you tell them not to! So far we have just kind of rolled our eyes and let her know that we do not believe that her, or anyone she knows are real witches or have any special powers. So far it hasn't had enough influence on her to affect anything like her grades, changing friends, or stopping any other activities, she's not obsessed with it every minute of the day.
I would appreciate and consider any advice anyone would like to offer on this subject.....thanks!