About your sexual orientation?
How did you know?

Idk, to put it simply, I thought this dude was attractive, I had a headache, several months later I realised. End of story.

In slightly detail, I guess the first clue was when I was 10, or 11 in UK Year 6, However I really only started questioning myself in year 7, around the time I turned 12, in the summer between year 8 and 9 I figured out the truth, and I have considered myself bi ever since, where around 20 people know and I'm about to enter Year 10.