That's interesting- are the women you are attracted to, or pursue, in their early 20's? Or are you just a young woman magnet ?
I don't see what would make it a generational thing, unless it is a case of subconscious reverse-feminism? I know many female friends who are attracted to older men, some of the reasons being 1) they are more mature, 2) they know what they are doing in the bedroom. I don't know if they like being dominated in the bedroom (and don't much care to know! lol) but maybe these young women you are speaking of enjoy submitting to older, more experienced men and then reach a turning point as they approach middle age where they become more confident, and perhaps more dominant? in the bedroom. Then they become cougars
Just a theory... and a weak one too! lol