Different males have different sized and shaped penises, just like hands, feet, fingers, toes, ears, etc. that all vary endlessly. All of them work fine and function for their intended uses. At 15 yrs old, you are honestly not fully developed and you're going to grow up more. Just compare your body to older guys and grown men and see how much more growing you have to get that big and fully grown up. But a lot of guys have small, medium ,and big penises at your age. Penises grow and reach full sizes at different ages on different males and in short or long growth periods of time from starting to grow to finishing growth to be full grown. Some men don't finish growing until they are into their 20s and some guys have fully grown adult men's bodies in their teens and get done growing earlier than other males. You really won't know how you'll turn out until you're in your mid to late 20s in many cases. By the time most guys have armpit and pubic hair their penises have started growing, but the order of which grows first and when can vary a lot from guy ot guy too. I'd just sneek a look and check out my Dad, brothers, uncles, and cousins penis sizes and shapes to see how big the penises of all of your male relatives are on both your father's and mother's sides of the whole family. Most males inherit their penis size and shapes from some combination of genetics from both their mother's and father's genes. Most guys are hung with penises pretty much like their different male relatives are, which can vary a lot from brother to brother and from dads to sons. You can also see which male relatives grow up early, medium, and later to see what to expect in your own family for when you'll be full grown. It all varies from male to male. But it gives you some idea of what to likely expect to grow between your own legs. I hope this helps.