I stumbled across it by accident when I was around 9 or 10 and was scarred for life and vowed to never watch it again but that soon changed when I got to about 14
Actually me and my cousin found ripped up pieces of a porn mag in a park once when I was probably 8, that really was weird LOL, I didn't really 'get' why such pictures would be in a magazine at that age, or what exactly was going on