Penis size, like height, weight and general build has been determined by genetics. When you reach maturation your body and its organs will stop growing. Most people reach maturation by the time they are done with the teenage years. Given your age, you are probably in the middle of puberty and thus probably are not completely through the maturation process.
Flaccid (unaroused) penis size varies greatly among men. There is less variation among erect penises since smaller ones tend to grow greater in size.
Since we are all different, you would expect some males to have bigger penises than you, while others will have smaller ones. The size of your penis does not say what kind of a person you are. This is important to remember since a lot of males seem to be concerned about penis size. Try to feel comfortable about who you are!