in my own situation, even with the benefit of hindsight, I am not sure what I knew about myself and when I knew it.
. As a 12-14 year old I recall be fascinated by greek and roman sculptures of naked men. but then I used to thoroughly enjoy going to "dancing classes" (I went to a single sex school, dancing classes and french conversation clases were done with the girls school on the next hill). through the latter part of senior school a girl I had known since kindergarten and I were considered a "couple". When at university (in a different city) I had brief physical relationships with both sexes (while maintaining the "relationship" with the girl "back home"). I considered myself straight....I think, if in fact I thought about it at all.
at the end of university I married a girl , we had two children. we bought a small business that after 5 years became a real stressor, causing the marriage to fail. six month after seperating I was picked up by a bloke in a coffee shop and had a 4 year affair with him (bloody disasterous, abusive relationship) at that point I figured I must be gay. 11 years ago I met my current partner and we have lived happily ever since.
Now when did I think I was gay? not sure. The only thing I insist is I am NOT "bisexual"; at this point in time i am not attracted to women in any shape or form. For all the time I was married (to the mother of my children) I was never attracted to any man.....
I never announced to the world I was gay on facebook or any other medium (I did tell my mother a year or so into my first gay realtionship, however as we were trying to fix a photocopier at the time, she replied that that was fine, but it wouldn't help fix the photocopier!)
"knowing" when I was gay - I really don't know....... and I am not sure it matters, to me anyway.....