How did you know you weren't straight?

 I don't remember so well, but I think I was about 12 and I realized I had a crush on my best friend ☺️. She was straight however, so we just stayed friends (we still are!). Now my feelings for her are gone. At the time I wasn't sure if I was a lesbian or bisexual, but a few years later I realized I was actually pan. 
How about you? How did you know you were not straight and how old were you?