I was 5 years old when I fell in love with her
Watching Dagger of the Mind on Star Trek TOS. Looking back on it now I realize that it was an epiphany moment in my life when I knew that from then on I was to be heterosexual. Thank christ! God she was beautiful.
It was the first time I can remember differentiating men and women as objects of desire. Or more accurately finding one desirous.