Timeline:
Around 7 or 8 I found my dad had some super old Playboys in the garage. The really old ones are pretty boing with maybe only 3 pages of boobs in the whole book. Around the the same time finding slightly more interesting stuff in National Geographic magazines.
After that, with some friends, found some porn advertisement on the side of the road with lots of images showing everything. Looking at it, I thought that girls balls looked pretty weird. I didn't know they didn't have balls. We ended up putting it in a neighbor's mailbox.
Then probably around 9 over at my friends house. He got on some bulletin board system, on dial up, and was downloading pics and it was so slow, somehow he had the photo open and it showed it filling in line by line as it was downloading. Was kind of cool in a way.
Lastly, around 10 seeing a black plastic bag on the side of the road while riding my bike. I got curious about it and took a look to find 2 full porn VHS inside. I had to play them on the living room TV just for a little bit while parents out of the room. One was called Mexican Gangbang or something like that. I remember thinking, why does the woman keep trying to talk with her mouth full? I guess she was probably just moaning. Regrettably I didn't want to get caught with them, so as was tradition, I put them with the bag in a neighbor's mailbox.