I'm asexual - it's not gay by any means, but it's still a sexual minority so I'll answer anyway
1. It was when I had just turned 15 and I'd never really thought about it before - if anything I just assumed I was straight I guess - but about that time I was starting to kind of wonder why I wasn't feeling 'attracted' to girls like everyone else, and I even thought I might be gay for a while, but I didn't feel attracted to guys either, so I was really in a muddle - at that point I'd never heard of asexuality. Then just by chance my biology teacher told the class to research homosexuality, and while I was doing that I went off on a bit of a tangent, ended up on the AVEN asexuality website out of curiosity and there was a list of criteria for being asexual which literally fitted me perfectly, and that was that.
2. It's just a part of who I am tbh and I can't really change that so I just accept it tbh.
3. Meh. In some ways yes and in some ways no. On one hand it's not well-known at all and my family still haven't really got to grips with it, so I still get comments like 'when you have a wife and kids you'll do this, this and this' and a lot of people tell me that there's something wrong with me/I have a hormone disorder(which isn't true) when they find out, which is really annoying, but on the other hand I don't see a pretty girl and immediately think 'how can I get in her pants'.
4. You know how as a straight person you just wouldn't get with someone of the same gender? It's basically the same thing for me but with both genders