I compare myself to all sorts of people. I might look at how a woman is dressed, I might look up a guys killboard in Eve Online and see the logic of how he fits ships, I might compare stories I write to that of other writers, etc. What I don't do however, is see someone doing something I care nothing about, like play football, and think how it would be to do that or try and see their strategy, etc.
So I think it is only normal to compare yourself to other people, in areas that you care about. So it would only be normal to notice what other women wear and compare.
For me, I tend not to compare myself so much to women who appear to be in different subcultures or age group than my own. I do however notice women that I am romantically attracted to, despite their subculture. I suppose I am not in competition so to speak with people so dissimilar to me, but dating someone dissimilar to me isn't weird at all.