First, this thread is not really about magic. It is about life as a teenager. If you want to do magic, then you have to control the setting and you never, ever, belittle an audience member (it is OK to use humor to defuse a tough situation--but, gee, if it were that easy, we would all be on the Tonight Show). Even in the worst circumstances, a professional magician will use a light joke and then peer pressure from the rest of the audience to stop a heckler. But this requires that the rest of the audience already respects you--and that they really want to watch the show
I have taught 13 to 16 year olds now for sixteen years and I see what you are describing everyday, sometimes in my classroom, directed towards me, and sometimes between the students. Since I have some status as their teacher, my best method of dealing with this is to calmly stop what I am doing, turn slowly towards the student, and wait.
I know it is different when you deal with some jerk who is your peer. You may be required to deal with it differently. The sad thing is that kids will give you status based on your ability to make the jerk look stupid. First, that is easier said than done, and second, this is not how you will survive as a magician (or in High School, for that matter.)
Just because you say, "let me show you a trick" to someone and they come over to watch, it does not mean they are really all that interested. You have to convince them in ten seconds that your "show" is worth their time. Face it, some jerk who comes up to ruin your trick may provide a better "show." If the rest of the audience refuses to support you, then, they are not your audience. It is time to smile and walk away (or put away your trick and beat the kid up—if you want to take the mature road
). Learn to be patient and pick the right time to do a trick. What you really want is for them to come to you asking for a trick (but still, never do a trick unless you control the setting). When that happens you will see more support.