I dated a guy 16 yrs younger than me and frankly there is a difference in culture and outlook on life. The younger guy is just starting out, the world is new, opportunities have yet to be realised, and challenges await. Maybe he hasn't started his career yet, or been through a serious relationship, or had to face the difficult decisions of accepting less-than-ideal things (e.g. work, education, relationships, housing) in order to make life work. maybe he hasn't lived on his own yet and hasn't had to fear unemployment, homelessness, managing bills and household stuff. maybe he's not sure what he wants and just wants to see what comes along and experiment. Maybe he hasn't done a lot sexually and isn't sure about what he likes, wants or needs from another person.
It also depends on your guy, but he may have been through much of it already, and can possibly share his experiences if he's mature and communicative. This will sound like a cliché, but he's probably been through a few jobs, been through a serious relationship or more, he knows exactly what he wants and what he doesn't need, he can see past the distractions in life. Maybe he's more sexually experienced and has unique tastes. Hopefully he's established a home, stability, a predictable income and work, and is probably looking to settle down and share it with a nice guy.
culturally, you will have different reference points: music, movies, tv, and what you find interesting and exciting to do.
these are all irrelevant though. its possible to overcome the differences, if you both make the effort. the young guy has to be more attentive to detail and responsive instead of just being all "yo" and "whatever". the older guy must be more patient and willing to let the younger guy face new experiences without rolling his eyes and thinking "been there, done that". physically you as the younger guy may just have more energy to do things or stay out til dawn, and you can't interpret the mature guy's mellowness or appreciation of comfort as him just being "old".
you know how everyone says that communication is key? it is. this means talking about all the difficult and confusing things in your head that don't make sense. this means not shutting off and going away when you don't know what to do or say. it means answering your phone when you'd rather not. it means replying to that txt or email when its complicated. it means that you're going to sound like a dummy sometimes. but it also means that you're sharing whats inside your head with him as he should be doing with you. good luck!