Everyone matures differently, women usually faster than men. Yet trauma & circumstances mature people too. Based on your experiences & your friends, is there an age that if a guy is not showing signs of maturity (accountable, stable, self-actualization, reliable, empathy) a woman should ditch him?
Nope. Men, like women (we assume), mature on a wide-ranging scale. It's less age-specific than man-specific. But, it might help if you determine for yourself how much you're willing to put up with or not put up with from any given man rather than worrying about the age of that men, since it's not the only or even best indicator for his relative maturity. Around the 28min mark of 'The Bonus Episode' we explain why http://www.twoguysoneshow.com/2015/05/21/bonus-lily-listener-questions-chivalry-and-more/