Penis hasn't grown?

my penis has not grown since I can remember?

I started to masturbate around 10, lived with older boys so they were always talking about it anyways, when I measured my penis and took photos (anyone that says they don't measure their penis is lying.. Fact) anyways I found my old phone and went through it, and it has photos of my penis next to a ruler, dunno how old I was but think around 11, anyways I thought I would do a comparison to how much I've grown. I am now 19 and my penis is the exact same size? Not even half an inch longer, the only noticeable difference is my penis now points to the left a little, the veins are more prominent and my penis is a lot more darker skin colour. (This is erect btw). I spoke to my friends and they said they started to notice their penis growing around 14+, how comes my penis hasn't grown? Is it possible I haven't finished puberty?