Yes its small but youre still a growing child. Men dont stop growing until their early twenties. It only matters how big it is when it gets hard soft doesnt really matter. So if ur 3.5 inches hard youll probably get to 5 or more in a few years and I personally think that's cool. Im a female and I would be fine with 5 inches.
im 12 and my penis is 2 flaccid and 4.5 hard, u just need to hit puberty,y voice cracks alot so I am already going through puberty so just wait a while and it will grow bigger.