I think I might be a necrophilia

I keep having fantasies about fucking dead bodies, using there heads as toys for me. I know I shouldn't be having these fantasizes, but I also don't really feel bad for it, it's just overwhelming at times, and I know it's not normal. I have no idea if I enjoy it or not, but I keep having urges about watching necro porn. Please help, should I tell my therapist? what do I do? I'm worried cause I'm still super young (early highschool)