I would frame this different to think about delayed gratification or as Bitcoiners refer to it; low time preference, do things for your future self and being able to think about your long term. Good habits in your 20's and 30's will reap huge rewards when your older. I'm 55 and benefitting enormously from just a few good decisions back then. For me, the future of my 20's and 30's is now.
People my age who haven't taken care of themselves lose muscle mass, bone density and strength. Fat around the mid-section greatly increases odds of getting sick. All of those inputs and getting sick (up to a point) are reversible. Lift weights and cut carbs. This will allow you to do what you want to an old age. That's me, yesterday digging line on a wildland fire exercise. 55 is kind of old for that but not crazy old but I keep up with firefighters less than half my age and have a ton of fun. Habits matter.