I'd say what decides if dating is good or not is if it improves your life more than it takes away, and that can happen at any age. I'm 43, but when I was in my 20's to mid-30's I did a lot of dating, and I preferred (by a good margin) the stuff after 30 or so. The part of people's brains that handle jobs like reasoning and good decisions don't stop physically maturing until mid-to-late 20's. So people may literally, physically think different before and after 25ish.

Anecdotally, dating after 30 was just nice because I got to skip some of the crap. I found partners that were content to live life at my speed. Not every date having to be an all-nighter in a club etc.