Yes def watch Harry Potter, they get better as they go on. I would also recommend the TV series True Blood. It's brilliant!
I'm currently watching Buffy the vampire slayer as I never was allowed to when I lived at home! It's rubbish but also good if that makes sense.
Speaking as a girl I agree with QMI I shamelessly loved twilight!! Also Vampire Diaries and The Originals (Im a teenager at heart!!)
If you like reading at all I recommend Tad Williams he does some epic fantasy book series full of magic etc. Also Robin Hobb is brilliant. Read Harry Potter and Lord of the Rings as the films miss parts out and change them about.
I love stuff like this and always did when I was still in......now I don't need to feel guilty!!