As a teacher, the hardest thing I had to learn was to model the correct behavior. They might taunt you. They might bully you, but in the end, if you stand your ground modeling the behavior you expect from them without lashing out, they will find respect for you. it won't happen overnight and you might think you are weak. however, having taught enough 13 year old how to behave without yelling or lashing out once, I can honestly say that it is worth the lashings(from them). I am still visited by old students to say thank you. good luck and be the person you are in the face of everything else. at least they aren't a class of 13 year olds
M