I live in Britain, so here I believe the equivalent is comprehensive school.
I suggest not trying to change too much to fit into a crowd. In my first year I didn't talk to anyone who liked R'n'B or hip hop or anything like that because I believed they were chavs. A lot of them were, but it limited the friends I could have. Most of the people from my primary school (your elementary school) I didn't talk to much after getting into comprehensive, but one of them, who was my best friend through parts of the first year, second year and parts of the third, turned into a backstabbing, selfish dick, which made it pretty hard for me, because if I said anything behind his back or I annoyed him, he could turn a lot of my friends who hung around in the same place against me, which he did do three times, making my life hard. I turned into a social recluse in the library for a while, but made new friends, mostly people a year younger, and one of them I consider family now, as they have helped me through some hard times.
All I can say is be yourself. If people don't like it, that's fine, but there will be people who do. Don't try and be the same as everyone else, as it won't affect the judgement people have on you and they will like you for something you're not.
Also, work hard so you can do well, but it's not really necessary until you have to do the exams and get the grades for college.