Im so confused....?

im a 15 yr old teenage girl, and im having trouble finding out who i am. it seems everyone at school has a special personality, some funny, mean, bitchy, depressed.... i have a good sense of humor but sometimes i say some things and embaress myself. i dont want to turn into a cynical person like everyone else. how do i have a good sense of humour with out going OTT.. any help would be appreciated!