From what I've seen, your age is going to put you somewhere in between a senior youth league and some local men's summer league.
Since you've never pitched before, you're going to have a rough fit with a competitive environment. I say this only because from what I've seen, older players don't play baseball, they compete. This stuff gets pretty intense and serious. Guys that have been together since junior high usually keep in touch, form their own little group, and compete year after year as a group. Hence, being a pitcher is a lot of responsibility and you've really got to hold up your end. I've seen little or no tolerance for a guy who can't cut it.
By the way, you'll see in these adult leagues the word.. " recreational.." but trust me on this one, there's nothing recreational about it. All of these people are hard nose competitors. Fun has nothing to do with showing up.