younger teen, and early 20's girls are confident, and dont care if they get shot down. the older women late 30's early 40's simply dont care. they know what they want, will tell you what they want, have already been shot down so many times what is one more time. older women simply know what they want and go for it. same for the younger ones. the ones in the middle are still trying to figure out exactly what they want in a relationship/man/life partner.
another theory would be that younger girls get fucked over alot by younger guys, so once they reach a certain age, the are sort of man haters to an extent. also being that younger guys fuck them over, they may look to an older man who is more capable of meeting their needs. weather they be material, or superficial.
guys are the same. ever see those old fat guys at the bar, hitting on 22 year old girls? they have no shame, and dont take no for an answer. also when we are young, we are mor into the chase. we are not all that much different from them...freak