i have heard the average penis size is 5-6in.you may be small or just still have some growing to do.but then again i am a girl so what do i know :)
You are only 15 and I am sure you have plenty of time to grow. Even if you don't then I wouldn't worry, an ex-boyfriend of mine was 4" when erect and we had a very good sex life.
Not to worry dude; get a girl that will teach you how to use your tongue and you'll have them all calling you for more.
When I was 15 I was 5'4" tall and my penis was around 4" long I went through a growth spurt, and went to 5'8" tall, penis 6"
You are suffering from a disease called micrphallus. Good luck Tiny.
if you are onloy 15, then that means that you are not done growing yet. you will have another growth spurt aroung 18 or 19, and you'll probably reach 6 inches or so, which is normal. the average dick is around 4 1/2-6 inches when erect. don't sweat it.
p.s. you arent suffering from a disease... don't listen to that other person!!!