Ignore them. It will show everyone that you are more mature than they are, and those who do not think of you as mature for it, are not worth the time and energy on anyway. People that age are just trying to show that they are something, and typically they do it in the worst and silliest way. Resorting to violence would only make you stoop to their level.
In time, if they discern that they are getting nothing out of it, they will get bored and move on. If all else fails, or if they begin to get nastier and nastier, then your only resort if to beat the living [bypass the profanity filter] out of them. If your school is anything like mine, the administration wont do anything about it if you come to them anyway....