Life Question about Friends?

So, I am considered a nerd at school, and I am proud of it. The thing is, there are these kids who are pretty chill, who I know quite a few of them fairly well. They are nice guys to me and stick up for me a lot, but they are not necessarily the greatest people to everyone else in the school especially the teachers. Me and a few of these guys hang out a lot more, and my confidence level has gone up. Consequently, some people are afraid of me now, and have attacked me because of the way I act(so I have to be all in or out out with this group). Moreover, I like doing homework on the bus, and show a lot of respect to teachers. As for the other kids, I know that at least one of them smokes(asked me to smoke with them), and do not have the greatest motivation to get work done at school. In general, I may be credulous when I say this, but I have a inundating feeling that some people feel inferior to me. When this happens, these people usually get aggressive to me, and the last time this happened I got a carbon-fibre hockey stick to the leg(never start a fight with someone who "outguns" you); as a plus, hanging out with these guys negates the previous problem. Additionally, the guys are not so disparate, because we both like the same music and sort of get along well. Should I risk my grades and have good friends, or stay cautious and just be friendly to them?