I'm 31, but I'm also quite immature, so I can't truly confirm or deny your theory. I enjoy it, it gets me much better flavor from my juice, and it's just plain fun to do in my personal opinion. I don't really do it to "show off", though, because I don't do it anywhere other than home. I feel it's just plain rude to blow huge plumes of vapor in public, so I also have an EVOD Twist I use with a couple mini tanks when I'm out and about. It's smaller, easier to carry, and not as annoying to the people around me. If I were to go somewhere intending to vape, say to someone's house who also vaped or to one of the gatherings people have posted about here and there, then I'd probably take my mod and my RDA and be blowing huge plumes. That's just because I'm around like-minded individuals, though.
It is very much like others are saying about sports cars and the like. If I worked on my car all the time, trying to get every additional ounce of awesomeness out of it, and I were in public on a main road, I doubt I'd have my music cranked, undercarriage lights on, and whatever else those people do going. Were I meeting up with a bunch of other people who ALSO tricked out their cars? Yeah, I'd show off everything mine could do.
As-is, I do it because I want to. It's fun to build my own coils (though my only RDA broke and I'm waiting on a replacement so I don't get to do it at the moment) and see what I can do, but it can also be about the flavor, the feeling of having something actually fill your lungs, etc. I noticed that the Blu I started with (which my fiancee now uses) seems like nothing compared to my EVOD, and my EVOD feels like nothing compared to my RDA.