Would Elfen Lied Be Okay For a 12-year old?

Elfen Lied has been a anime that I have been wanting to watch for a while. I heard that it was a BIT "gory" and read a review. Turns out it has nudity, violence and "darker themes." Sure, I've read manga a bit like that before only not as intense, you could say. It the review said that with the violence would is the most prevalent thing though. Apparently it's rated adult mostly because of that I'm a 12-year old girl. I'm not that much of a little kid, I'm pretty mature for my age. I can deal with blood and stuff like that, but I'm really not sure what to do. I bet my mom would find out too... SO should I watch/read it? (I need some legit advice here!) I would have to buy it at the book store with her too...