Maybe I am misremembering my wasted youth, but isn’t horrifying your parents the main point of listening to heavy metal? or any music as a kid. I am firmly convinced that the only reason my daughter likes Selena Gomez and Big Time Rush (she’s 10) is to send my metalhead brain into convulsions of horror at the very thought of that noise coming out of my car speakers. 
Lord help you in 6-18 months when you discover masturbation.
MetalMaster, I’ve been listening to Hard Rock and such since 13, I am 18 now and still listen. I love it. I also hid it until I was about 17, that is when I actually felt comfortable telling them. And I did, and you might be surprised.
Just wait until you are comfortable telling them 
I am also religious, and I am strong in my faith, my music doesn’t make up who I am but it does contribute, in fact it has helped my realize very important lessons
do not be ashamed in your music, just be respectful to those around you with it, that way you don’t get people going at you, and you can enjoy it in peace.
one last thing, find others who listen to your type of music, so you have someone to talk about it with that always helps.
I wonder if OP listens to Rob Zombie.
I am a Metalhead, and not to sound rude . . . but that was a fairly small-minded post. I didn’t grow out of Metal, and I won’t any time soon. Metal isn’t always just some teenager phase, it hurts me when I find people giving Metal this stereotype.
With the OP now being at least 16 and presumably having resolved every issue he’s ever had with his parents (as all teenagers have by the age of 16), I’m going to close this one.
Celtic755, welcome to The Straight Dope, and feel free to start a new thread if you want to discuss metal more generally. We generally discourage the reviving of very old threads without a very good reason.