It depends whether you are a boy or a girl.
Those averages are a good place to start, but remember that a lot of people are smaller than average and others are bigger than average.
Average just means the middle... you shouldn't be worried unless you are having some sort of medical problems... if you're worried your friends, your gf or bf will make fun of you, they're just being a jerk... or they don't know any better
every size is normal.