Jedi Knights are not real. Witchcraft is real. Huge difference.
Unless you've been to a galaxy far, far away, you don't really know that.
1. What? Jedi knights aren't real? How did you figure that out? Did you operate under the delusion that they were real until you were 18 or so, or did you know you were watching a movie? Or, did your parents shield you from the evil that is Luke Skywalker?
2. The Force shares some aspects with Eastern religions. So, perhaps a better question would be, did you see a lot of kids coming out of Star Wars screenings and converting to buddhism or the hare Krishna cult?
Like I said, any kid who goes into witchcraft after reading a OPotter book is a nut with dumb parents.
Have you been turned into a toad recently?