I really can't recommend this show. It has some interesting bits but there's just too much sexualization of clearly underage characters.

I mean sure the main heroine is an immortal vampire who's hundreds of years old, but then the show does this creepy thing with a high school girl lusting over a little boy and somehow it works out because for some reason he feels the same way and they both become vampires so they can be together outside of society's rules. Even with the immortal vampire thing going the kid is still like 11.

Well she is a vampire, so she's clear…

(Side note: The source is "Dance in the Vampire Bund." OP should have listed it in the tags.)