because your 14 and still ging through puberty
when you turn 18 and hae finnished puberty it will be fully grown
remember that whatever size penis YOU have is normal for YOU
that is normal I have 3 brothers and now I have 3 sons and as you get older it starts to grow. you are still young and you still have a lot of growing up to do. some people just develope a lot quicker than others. but just give it some time to let nature tak over it's coarse.
it will grow