I have never talked to a gay person and had them tell me they were gay upon our first meeting. Most only reveal this because it is relevant to the conversation or someone else revealed it about them or it is revealed by who they are dating or mention they find attractive. Just like heterosexuals. I thought my roommate was asexual for quite some time until he finally got a girlfriend while we were sharing our third apartment. I found out it was just that he was attracted to really big women. He had no interest in women less than 200 pounds. So he appeared to not have any sexual interest because he wouldn't be attracted to the vast majority of the girls in the Navy (given that we have to maintain a weight way below that, no matter the height) and most of the other guys would point out women who were smaller, who simply didn't turn his head.