The point is to focus on how good you're feeling while you are clean - and really focus on it. That's part of staying clean, that's why you go to therapy, and/or (take your pick of) meetings, phone calls with friends, sponsors, partners, logging onto GYE and posting. Remind yourself. It's too easy to forget about it when things are easy...until they're not.
Posting and talking to people also helps you keep tabs on how you're doing. Usually, when a fall is coming, you see it coming- if not from a mile away, then at least far enough away to make a quick right turn and hightail it outta there. But when we're alone, we can miss it because we're not paying attention, or more often, just ignore it, or say things like, "but I neeeed this (insert whining tone - we've all heard ourselves say it)!" Or, "it feels so good, I just CAN'T resist!"
As far as whether younger people can get clean? look around on this site. I was in my 20s when I started here, and I was clean for well over a year and a half. Maybe even 2 years? Not sure.
More importantly, though, it's all excuses. You're trying to say the old argument, that for guys like you (whether because of age, high sex drive, particular situation) it's just not possible to really stop.
But it is - if you decide that it's worth it.