I used to hang around a group of friends back in Year 7 and 8, since Year 9 and as time gradually passed, I started to hang around with different people and within another friendship circle. Even though I got good grades, my friends haven't exactly been the most supportive of me, my friends just always end up criticising me and everything I do, and I started sixth form earlier this Monday, and I've gone back to my old friends who have gladly accepted me back, and I enjoy being around them more.
At the end of the day OP, make the decision, find some new friends that also care about their education. The friends that I ditched just always seemed to talk about Call of Duty, and "Oh that girl looks fit, I'd do her", and nothing else...