I found myself telling variants of this story on the comments to a few people's posts last year - so if you get a sense of deja vu reading this, you were probably one of those people! I can only apologise in advance.
The first Valentine's Day I remember was in my first year of school - shortly after my fifth birthday.
Not everyone at that age seemed to have grasped that Valentine's Day was about couples, and some of the children sent cards to everyone in the class. I'd somehow understood that the cards were supposed to be for secret crushes, and since I didn't get a crush on anyone until I was about fourteen, I didn't send any. (In fact, I've only sent one anonymous valentine in my life, but that's a story for another day.)
But although my understanding of the 'grown-up world' stretched as far as Valentine's Day, it didn't go quite as far as knowing about lesbians.
If I'd known that, I might have been a bit less stunned that my first valentine's card was from a girl. In fact I was just confused, because she definitely didn't send cards to the whole class.
Photo by philippe leroyer on Flickr (creative commons)