I've always been confused by this question of what sexuality I am. When I was younger, I thought myself straight since that was the norm, and my parents aren't very tolerant of people who are gay or bi. (My mom actually has told me that if I were to say I was gay they would beat me until I was straight >.>; ) So I just assumed this, even though I never really had any interest.
Then started high school, which was where I started getting confused. There were a few of my friends, who were guys, who I really liked and could imagine being with them. I thought myself gay then because I still wasn't really interested in being with a girl (Although I did have quite a few girls I considered friends, just no interest in taking it beyond that). However I still had no physical attraction really, but I tried to just ignore it.
Not too long ago though I had heard about asexuality, and I've come to believe this is me, simply because I have no desire for sex. I am curious about what it's like, but could easily live happily without ever knowing. I'm not aromantic though, because I really do want to find someone I can love and be loved by. Someone to spend the quiet moments with...etc, but in this regard I'm bi, as I could spend time with someone like this of either sex.
Whether or not I chose this, I don't really think so. I chose the label of course, but it's just how I've always felt so I think it's more of a nature thing with a bit of nurture as well.