I personally LOVE the show. Me and my mom really got into the show ,when i was about 11.
Although somethings i admit where a little bit to mature for me,(and I normally would just fast forward past them Or skip the whole episode,since the more mature ones would bore me) I found it to be a really good show.
Phoebe,Piper,Prue and Paige are actually pretty good role models in my opinion . I mean they often risk their own lives to protect others, even if they can't stand the person.
And they also enforce strong family bonds , being selfless , thinking BEFORE you act , following you're instincts and your gut feeling.
The violence isn't really a big deal, everything is "tasteful" and nothing is to bad gruesome. If you'd let your kid watch any of the CSI'S or NCIS Or Castle ..I'd say green flag for Charmed , because those shows show way more than Charmed ever did..