A scary movie about a little girl that is haunted by the Devil's followers?

I remember watching this movie when I was younger. It was about this little girl who's mom was like a demon or something and then the devil tries to get her. Oh, and the mom has some freaky tattoo and so does all of the followers. If anybody remembers this movie, please let me know. The little girl like goes to a Catholic private school and at the end of the movie, she goes into a Catholic church and she has some kind of necklace that protect from the followers. I am not making this up. As ridiculous as it sounds.