This might change as I get older, but now I'm 28 I can openly point to men who are 40-55 who are easily the same level of maturity, income, and stability as I am. I think once you hit 30 (ish) as a woman, you can date as old as you like. It's mostly about the big three (assets/property, mobility, emotional stability). Very few women 30 and up don't have somewhere to stay if it doesn't work out, a job of some kind, a car, bike or access to a train or bus, or experience in a relationship. In my opinion. I could be wrong.