Older men frequently hit on me...thoughts as to why?

Whenever I go to gay bars, which isn't very often, I frequently get hit on by older men. I never go alone, but I find that if my whoever I'm with gets up for some reason, such as to get another drink or use the restroom, an older man usually comes and hits on me. It's usually really overt, a little uncomfortable, but when whoever I'm with returns, the older guy scrams... I just wonder what it is about me that older men gravitate towards, or if others of you experience this as well? I think it might have to do with the fact that I look really young...? I am 22, small, thin, nice skin, big eyes...perhaps it's the youthful features that attract them...I'm really not sure. Interested in any thoughts.