I very much disagree that most of us started dressing for sexual reasons. I first wanted to wear "girls clothes" when I was a little kid, with memories as early as pre-school of wanting to play dressup and feel pretty. Sex hadn't even entered the picture yet. I think it's the repression of those desires that leads to later fetishizing and sexualizing.
But this isn't a discussion of why we started dressing. So far the responses have been interesting to read, keep them up!