it depends on the age of the people involved. if you're 30 and with someone who's 41, that's less difficult than being 25 and with someone who's 36 (although you've advertised that you've already passed the more difficult stage, and in theory, things should be getting easier).
the reason people are concerned is it's difficult match interests, concerns, even relatable experiences when the gap is large and the age is low, but everyone tends towards a general commonality.
e.g. at 20 it's pretty common to find people very much into extreme sports and binge drinking. as well as knitting and homemade bread. at 35, you'll find far fewer people participating in the first two and far more in the second.