There are all types of people in the world, therefore diff preferences. I have met a few of my friends who went out with older men, and they still prefer older men over younger or the same age. They say older men are more understanding, mature, and economically stable etc etc etc. A gap of a little bit more than 10yrs was basically the gap my friends were into actually. It's not like do younger girls usually consider older men, it's more like, if there is chemistry with a man, age does not matter.
On the other hand though, I'm the type of women who is attracted to men 1-3 years younger than me because they'll make me remember of the fun times in high school, and doing things without thinking. I'm attracted to men who are shy at almost everything and not so experienced, but that's just my taste.