Willfully Asexual?

I was trying to figure it out yesterday.  I was walking in the city heat looking around there were a lot of people milling around and most of them were young people.  More than half of them were women or girls, but being make I may have only noticed the girls and not the men.  This, I am told, is perfectly natural for men.  There were women with large busts and tight clothing, women with plunging necklines, women wearing tank tops, women wearing just bras and there were women in short shorts or mini mini skirts.  

I was looking at all these girls, mostly in their twenties but some clearly younger.  I was looking at them and seeing their beauty and not feeling anything at all.  They were attractive, they were comely, and I was not interested.  

This, I realized, is demiromantic for you; seeing the beauty around you and not being interested in at all.  I was interested in that they were pretty women.  But not interested in sleeping with them.  It is true, I have a girlfriend, but it has always been that way, or has it?

Did I realize years ago that girls might not want strangers leering at them and pawing at them with their eyes and decide that I was not going to do that and because of e nature that is me, that desired behaviour became locked and part of me.  Could that be it?  Could I be on the Asexual Spectrum because of an act of will?