Oh dear.
I'm a 54 year old woman, and I'm a bit of a vagabond type myself (imagine aged Debbie Harry and you won't be far off!)
I date younger men all the time (don't feel the need to list my conquests to them tho!), and would date a 28 year old for a while, no problem. I love the energy of younger men, I love their outlook on life, and frankly men my age seem like my dad, and mostly bore me. If they aren't up for a midnight hike up Swindon, I'm not interested - and so few men my age are.
But by the time you are in your 50s, you are set in your ways, happy with who you are, and are looking for utter perfection to even consider settling down (well, I am anyway). It will doubtless be different for men, but I would never settle down with a 28 year old. I'd basically be lining up a carer, and that isn't fair.
So we have fun, I teach them lots (and they sometimes teach me some), and then we both move on. The relationships generally last about 6 months to a year maximum. If that is what you are looking for, go for it! If you are looking for marriage and babies, think again.
It sounds like you don't actually know him that well, and are looking beyond the vagabond exterior, imagining he has a soft heart of gold underneath. Projecting your own good qualities onto him in spite of any evidence to the contrary (listing conquests? Yuck!).
If you go into this, go into it with your eyes open. Any outcome is possible, but some are more probable than others.