As has been said many times, it depends upon the lady involved.
Most the ladies I see are in their late 20s through early 40s, but the same thing applies to them. I am experienced enough to know that some of what a lady says is marketing, and not all ladies have the same reactions. But I also believe that without a doubt most ladies prefer older gentlemen. How many "No one under 30" ads to you see vs the number of "No one over 40"? There are some, as as with any preference a lady has it's good for them to say so up front.
But beyond the words, I go by their actions. And the actions say many of the younger ladies have absolutely no problem hanging out a bit over time or even going out to dinner OTC with an older guy.
Sometimes I think the guys who keep asking are a little insecure and jealous of us "experienced" gentlemen.