We've done it the other way around. I'm the Older Woman (by 12 years!) and he's the Younger Man. It took me a long time to even remotely consider him as partner material becuase of the gap. In the end he backed away becuase it was too painful for him, I realised how damn much I missed his friendship, and that made me give it a go.
Biggest disadvantage? Experience gap. It was there, it still is, and sometimes it's really frustrating. He was slightly cocky, thought he knew it all and I was left trying to tidy up the messes that happened because he, well, didn't. Very annoying sometimes. But he got a lot better at talking things over and realising that I had actually -had- some experience of plastering a wall or whatever. Secondly, as someone said higher up, when yo're a bit older things start to creak and you ain't quite as physically resilient as you were. Which wasn't very resilient at all in the first place, for me. He doesn't understand those limitations yet, but he's learned to take it into account.
Biggest disadvantage from his POV? YOu know, I'm not sure. Have to ask him!
Biggest advantage? not to do with age really; we both really wanted the relationship to work, so when we got to the really nasty patches, both of us kept trying. Admittedly for the sake of the son who came along, at points. But we've both kept trying.
I think the next biggest advantage was also experience; mine. I knew how to try to nudge him in (what I think of) as a good direction. Maybe that's arrogant, but I've had two LT relationships before and he had only had one short one. It takes time to learn to live together and it helped that one of us had already gone through it.
You said you're no spring chicken. I assume that you've both had previous relationships then? that should help. Also, if both of you are within stones' throw of experience with things like having worked, having travelled, culture etc .. those things are more important than age.
Oh, my first LTR was with a man 14 years older than me. I was 18. Big alarm bells you might think, but I'm truly grateful for the time we had together. He taught me so much about the world and he pushed me to think for myself. Great bloke, still friends.
2nd LTR was with someone my own age 