For the purposes of this post "Straight Edge" means no alcohol, tobacco or recreational drugs. Some definitions take it farther than that, but I just mean the basic one.
But yeah, I'm in my late 20s and have never really seriously partaken myself due to lack of interest. The only times I can recall are accidentally taking a drink of someone's Bloody Mary when I was a kid (Which I still remember was spicy as fuck decades later btw), and getting some 2nd-hand pot smoke at a friend's house once.
If you do, I don't judge, just try to be careful/not overindulge is all I'd say.
I don't really do "anything". Never drugs or alcohol. I used to drink caffeine but not for many years now. I am in my early 30's.
Always by choice though. I always saw substances as either a temporary yet damaging thing, or just trying to escape reality. Pizza, videogames, movies, hanging out with friends were always enough fun for me. I never felt the desire to lift my brain to a new plane of existence with drugs.
That said... life sucks. It's basically made me a loner and a hermit because most people indulge in at least something as a part of socialization.