Its natural for younger women to be attracted to older males, once they get into their 30s it will change a bit, a 21 year old girl would probably find an 17 year old male too young, but a 33 year old female wouldn't be a problem with a 29 year old male as she will respect him as being mature enough to be at her level.
I would say with older women theres a big difference depending on whether or not they have children of pre-teenage age. When a woman has a young child then her instincts switch towards nurturing the child and she loses some sexual energy imo, her instincts are not telling her to find a mate and breed, like they are to a woman without a child. However once her youngest child is getting into the age of independence, older teens etc, then the sexual energy can come back.
You do find fiesty confident women in their 30s, usually intelligent career women who have downgraded the idea of families or children while they were getting ahead, then suddenly decide that the "time is right" and their breeding instincts make them randy as anything.
However, one problem with older women....you know how amongst people of student age, girls complain about the type of needy 'nice guy' who does their heads in, trying to befriend his way into bed with them, and when he finds out his 'friend' isn't interested in a relationship, he becomes bitter, spiteful and full of hate for women (and probably comes posting on TSR, I'm a nice guy, why do women go for jerks and so on). Well once you get into people in 30s and 40s, the female equivalent of this appears. The woman who is a pleasant enough personality but not especially attractive and a bit boring...so then will go complaining to her friends, or anybody on the internet who will listen, that she's had it with men, they are all bastards, she's a nice woman who just wants somebody to love/cuddle/hold hands/share moments/other loveydovey stuff with. You don't see this so much amongst girls in their teens or 20s, because at that age, females hold some social power over males as the primary 'choosers' of mates....at this age, most men are just horny and want to get laid, but women are by nature more choosy, so the average girl gets a lot more attention than the average guy, and she has the power of veto. Once you start looking at 30s and 40s, the social power tilts towards men, at this age the single females are pressured by the biological clock, so they are then becoming less choosy and just wanting a man, whilst the males, especially if they have got a good job and are established in their careers by then, are in a powerful position.