My answers:
1) I was probably six or seven and dad subscribed to Playboy briefly. I had no idea how much I'd later wish I'd stolen a few and hid them away until puberty hit. Four years later my best friend and I combed every inch of my house, sure that my father would NEVER throw something like that away. (Dad, btw, is a minister.

For a while, Playboy offered free subscriptions to men of the cloth to prove the magazine was a lot more than naked women.)
2) 1981. I'd say 14... I was riding my bike to the arcade and saw a weather-beaten magazine tossed to the side of the road. I stopped out of curiosity and saw it was an old "Oui". Words can't describe how bleedin' happy I was.
3) I was assistant manager at a used book store in 1984 and was 16 years old. The owner (a woman) was letting a good customer hide his collection of Super 8 Swedish Erotica films in the back storage room - so he wouldn't get caught by his mother. She hid 'em pretty well - but I was snooping around for a copy of a book one day and found 'em. A day or two later, I snuck one home and set up the ol' home movie machine and watched my first porn film. Ah.... happy days!