My memories from when I was 13 are fuzzy, but from what little I can remember, no, 13 year old girls with boobies are not common. There were maybe 2 or 3 girls that stood out among some of my classmates for having what they called "tits" and that was it.

This guy either never went to school or his porn addiction made him forget how real humans look like.

Who the fuck starts a post like that, I just sat down.