embarrassed about late puberty

So I'm 15 1/2 years old and I still have not hit puberty and it's embarrassing. Almost everybody in my grade has but me, I hardly have any leg hair, my armpit hair is growing but if I lifted my arm you wouldn't know, although I do have pubic hair which I've had for a couple of years now. I have not talked to anybody about although pretty much every body knows it because it's sort of obvious. My voice hasn't really cracked and it's still kind of high. My penis length varies though, some times it's only 1.5 inches sometimes it's more than 2 inches. I'm just wondering why I haven't hit puberty and I'm really waiting for it so I can't be picked on at school anymore. If you looked at me you would probably guess I'm 13, my face has hardly changed since I was about 6. As well please don't say I'm a late bloomer