How can I become more respected?

Some people tell me that I am immature and that they are embarred of me, I'm 13 so I should be on the brink of matureness but I don't seem to be getting there, all of my friends can actually control themselves as in like... be silly when they want to but then when they are like at school in front of all the like 'popular' people they can keep calm I can't and it's utterly embarring. Help! :o ( P.S: I need help, I do not need to be told that I need to be myself and that if my friends don't respect me then I should not be thier friends, but that is not what I need to know I need to know how to control myself and make myself a bit more like them.)