This topic was really hard for me - not because I didn't have forbidden knowledge at a young age, but because I can't remember a time when I didn't.
It really sucked having to do the whole "Great, Santa is coming" line of crap on Christmas morning at 7, 8, 9, 10, and a few years thereafter, when I knew my folks were lying to me. How? Um, because I was a KID. I had to get something out of my parents bedroom, even though I knew I wasn't supposed to go in there, and I should wait until they got home to get it for me, a few daysbefore Christmas and stumbled upon the stash of Christmas presents sitting under blankets, etc in their bedroom.
Fast forward a few years, and we see me at 11, knowing my parents are freaks! Why? Because they - gasp - have sex! How did I know this? Did I walk in on them? Um, sad to say that wasn't what damaged my fragile psyche. Nope, it was worse, I was in my parents room getting something (again - I was a KID!) and it couldn't wait until they got home to get it for me. I found a dog-eared (the horror of that alone - WTF dog-ears a book?) copy of the Kama Sutra, and some really interesting novelty rings with couples having weird sex on them. Yea know what I am talking about - 69 and woman on top stuff. LOL
The best memory for me though, is at 13 we were visiting my grandparents. And I had started reading romances. And my grandmother would go to the used bookstore and load up on them - the old Harlequin Presents ones and some Silhouette ones as well. She'd get the value boxes, where the store owner just tossed in 10-12 dozens of books and sold them for $2-5.00 or so. And often times, she wouldn't even check them out, just bring the box home and sort through them later.
So we went visiting, and I got to go through her newest 2 boxes. And I read those things like they were candy. The best one though was a secret - no one could know about it. Because somewhere, a goof had been made, and poor grandma wound up with a lesbian romance in her box. And oh what a romance it was. The characters got sexy-nasty with each other. The best scene involved a candle being used in place of a dildo - a term I didn't know at the time.
Keep in mind - at 13, I was naive. I had only kissed one person - a girl (because we were both curious). I only knew about sex from romance novels, and not always was it nice sex. So that book was an eye-opening experience. It also started the faint knowledge that something about the book was captivating to me. Something about two girls caused a curious melting inside of me. The same kind of curious sensation I got when I read about a man and a woman.
While reading this forbidden book of two girls, I had my eyes opened to a new world of possibilities. And got my ass grounded when my mom found the book days later when she was packing my suitcase to head home. Oh the shitstorm that created.
To this day, I have tried to find that book again. But without knowing the author or title, it is hard as hell. So if anyone reading this knows of an old lesbian romance which involves the characters using a candle to have sex, let me know.