I think it depends on the age. There's one man I've known since he was 20 and I was 24. At that time he was too young. He needed to grow up and I needed to get over my age hang up. Now that we're both older the only thing holding us apart from trying something is distance. He is now 24, mature, in grad school etc. He has actually reached out to me to thank me for not rushing his maturity process and for allowing him the opportunity to become a man. I never wanted to rob him of the chance to grow up. I mean, I had my early twenties to act stupid, make mistakes and learn so why would I deny him of the same.
OP, really assess this man objectively. is he mature? Has he shown that he's alright with the age difference? Does he still need room to grow?