I love my high school...While there are cliques in my school I just don't participate in them. I hang out with pretty much everybody and sit at like 5 different lunch tables.
I think it really depenRAB on where you go to high school. My school had only one person, besides myself, I knew who was into folk metal and all that Scandinavian stuff. However, the area I am in has less metalheaRAB and more fans of hip-hop and pop. I think the bottom line is that you won't have a problem unless you bother people about how good your music taste is or how much their music sucks.
I think though, that if you are going to come to America to enjoy the experience then try to learn to appreciate American culture while trading off some of your culture with others. While you may not like country music or hip-hop, I would suggest listening to some so that you will get more of a taste of the culture. Enjoy America, because it really is a great place, despite what many people will tell you.