I entered junior high school in the late 60's. I was definitely curious about boys' penises and seeing them naked. In gym class which only lasted an hour, most did not shower given it was a hustle to get dressed and be ready to go to the next class. But on occasion some of the boys did shower and they were the one's well into puberty and sporting pubic hair and large penises. I definitely looked but tried not to stare.
Keep in mind back in the late 60's, anything that had to do with same sex interest was so taboo to the point that most really did not know much about it, but it was seen as very negative if it was ever talked about. So, you would never want to even admit that you had any interest in boys' bodies. My interest like most boys was to see how far along they were in sexual development compared to me. But there was a deep-seated sexual turn-on lurking inside of me.
Given that if I saw myself as heterosexual, it was very scary to contemplate any interest in the same sex. The shame that society had smeared on same sex interest was so severe that it left me very conflicted about even thinking about possibly enjoying sex with a man.
But I finally got up the nerve to meet a wonderful guy here on zity who has a passion for enemas equal to mine. We met and had a great time, and I realized I was very much bisexual. I realized that I was not gay at all, but I could enjoy and find sexual fulfilment with both sexes. Once I came to this realization I was at peace with my sexual identity and the fear and shame of being with men went away.
So, it all started with that curious interest seeing boys with large developed penises in the gym shower and being quite excited. I now look back on that fleeting memory and know I was always bisexual I just had to discover it for myself and embrace it.