what do you think made anya realize she was a lesbian?
lack of attraction to men was the first sign, probably! this is something that anya hasn't exactly been consciously aware of, for the most of her life—for her, she always just had this feeling she was different from her peers when growing up. she wasn't quite like other girls—always a bit quirky and unusual. when girls her age started crushing on boys, anya simply didn't.
being raised by 'traditional' russian parents didn't aid in her discovery, as neither of her parents were particularly keen on informing her about gay people—at the same time, though, it wasn't the worst it could be. neither of them really pressured anya to be with men, so there was that.
anya most likely would've discovered her attraction to women in a distant, faraway manner—through media, after moving to america. maybe through some of those reality tv shows that are her guilty pleasure. maybe she saw too many sexy women on tv and eventually realized, 'oh, god, i'm into them! now it all makes sense!'
...but that'd likely not be something she openly shares, or admits to herself too offen. now, in a scenario where she develops affection towards another woman, THAT is where anya would, for sure, acknowledge her lesbianism. without a shadow of a doubt. falling in love with a woman would definitely make her realize that she is, in fact, so gay.