admit it you are gay and you like Kami's dick
This should be a standard response to all things.
Anyway, as to the topic. I realised I was gay when I was 14, mostly because of porn.
There really were no social outlets or anything else for me to interact with or completely understand what homosexuality meant - my mother and father had drilled me with the notion of a gay man being a man who wanted to be a woman, the sexual orientation part was never really mentioned. The kind of films seen on television were also controlled by them and because gays are icky, I never really got to reconcile myself to it and I wasn't in school at that time. So this meant that the idea of 'gay' was only brought him to me when I discovered a medium I was in control of ... the internet and like all horny teenage boys, one of the first things I looked up when my mother's back was turned was porn.
I was kind of grossed out with porn, mainly because the guys were gross and so I looked and looked for porn that had attractive men, preferably several at once with one woman. Hit home very quickly that I just didn't get turned on by the women and then I saw an advertisement for gay porn, clicked it, and found it entirely interesting. Once I'd gotten used to looking at it I started to look up sites about puberty and sexual orientation and such, realising what I was and what it meant.
All of this happened in maybe the span of two weeks and before then I just didn't really have a concept of what sexual orientation or sexual attraction were. I just wasn't self aware enough to realise what my body was telling me then without the confronting material of porn and the educational materials on the internet. Before I became aware, I never experienced any desire or response to women or girls of any kind beyond the expectation that I too, like my sister and all my cousins, would eventually get married and have children but I was curious about the male body.
In retrospect it should've been quite obvious when I was little, I ran away from the girls who had cooties in kindy but made out with boys quite a lot. Ran away from the girl who tried to show me her vagina but played 'house' with other boys.
So that's the story of how I became aware, basically. Nothing 'turned' me gay and I can recall lots of consistent signs of my orientation even going back so far as pre-school but it wasn't something I really became aware of until later. I think it would've been a much simpler process if I knew at least one person who was LGBT though (didn't meet another till I was 19), and I wouldn't have been so depressed after realising, either, I don't think.