I'm in my mid-30's, so why can't I think of myself as a grown woman?

This is a tricky question to ask in a clear way. You see, it is not a question of whether I think that I am mature or adult or whatever. Rather, it is a question about why I can’t see myself as looking sophisticated, “grown-up,” adult, alluring, etc. I am in my 30’s (but I am constantly told that I look young for my age). I am trying to figure out why my self-image (of my physical appearance) is that of a (maybe kind of cute) girl, rather than a woman. Any suggestions for looking and feeling more like an adult?