Spanner; this is your close reading homework,please complete for period 4 on Friday.
Back to OP, as much as I have taken the mickey,I am a teacher. If this guy is not local and has been to lots of schools, these will not be the sort of pals who will back him up. Rather than that, they want to see him go off on one, and they hang about with him because he behaves in a way they dare not,but find amusing. All he has is his reputation for kicking off, he obviously has nothing else, so has to reinforce that to gain a small foothold in the teenage pecking order. If it was not you,it would have been somebody else.
It must be said that I find it hard to believe you were not aware of this guys behaviour before the incident,as all the kids at my school know about our more interesting pupils. As has been pointed out, if you had not just ignored him ( because he was 3 years younger than you?)and said sorry,then what little status he has would not have been challenged. But that is a choice you made,perhaps you might make it differently next time.(I wouldn’t have at your age)