I was born in the UK. We lived in London until I was twelve. In the last year or two I was there, one of my friends or I would occasionally get our hands on a girly magazine, which was always passed around and enjoyed. When I was twelve, we moved to the American Midwest in a fairly rural area. The culture shock was intense, but that's not important here.
There were only two schools: elementary school (K-6) and high school (7-12). In physed, classes were lumped together 7-9 or 10-12. We all used the locker room at the same time, however, so that was the first time I saw naked adult males. Seeing some of those big strapping farm lads of seventeen or eighteen, muscular and hairy with adult-size cocks, was an amazing thing for me. That's when I realized I liked both girls and boys. As an adult, I've been more gay than bi and have been in a long-term relationship with a man for a decade, but I still like women, too. My partner is the same way, and on occasion we hook up together with a woman. (Sadly, not lately because of Covid.)