i think it could be said thay younger guys would prefer someone older and the older guys would prefer someone younger.

im 22 and id prefer someone older,in her 30's for example as it would show shes mature and experienced,and can look down on me.

other times im happy with someone the same age as me but the atmosphere is different,its more of a 'do it for fun' thing as i wont be able to take her as seriously as the older woman.