Age differences shouldn't be held so high. I eat lunch at work with people 3x my age, and we have plenty in common. We often learn things from each other, and they're very valuable friendships. I wouldn't hesitate to invite them to do something which we share an interest in.
I find it is easy to get along with a wide range of people of the same age, probably because of similar circumstances and concerns (get education, find a place to life, get a family etc), even if the chemistry is not that great.
With people of different ages it's far harder to work around that, and easier to notice when the chemistry is great. It's fantastic when it works out like that, but difficult or boring if it does not.
