Should I not listen to Heavy Metal?

okay so I listen to heavy metal (Slipknot, Slayer, Bullet for my Valentine, Disturbed, Killswitch Engage) and i love it. but my family goes crazy when i listen to it. my dads side of the family says is "demonic" and can posses me? my cousin and I love Slipknot and they took everything of Slipknot he had (shirts, posters, dvds, cds) all of it. he even had coreys mask and they took it away! and they gave me and him a long speech of pentagrams and the devil and church. Okay now my moms side. My sisters call me a freak sometimes saying all the music says is "DDDDIIIIEEEEE" and my mom says everytime she hears me listening to it she wants to punch the radio. Like i bought a slipknot shirt the other day and they got all mad saying wtf is your problem and stuff like that. And finally today I want to go and buy a slipknot DVD and my dad is questioning me saying "why the hell do you want to spend your money on that crap?" and im tired of their crap! Should i stop listening to metal (which will be my last resort) or stay a maggot and if they say anything just try to ignore it. Also i want to buy and put up posters of them and paint my room a darker color because right now i have my room nothing but Redskins (my favorite football team) the walls are burgondy and gold. should i ask to paint it or just leave it and put up posters? THANK YOU FOR READING THIS LONG STORY AND ANSWERING! STAY SIC