So for the op, I think about this whole aging thing a lot. More about getting older rather than the actual aging process and I've read some articles about it. Basically it has been said that one's 40s is the most depressing decade as far as that goes. People in their 50s don't seem to care as much, in their 60s they seem happier than they've ever been, in their 70s they are just thankful for each extra day above ground, and who knows Beyond that.
What might help though is to remember that at our age the world does not try to bullshit us as much. We actually start to gain a little respect. We also start to accept our lot in life instead of chasing unrealistic dreams or wishing we had things that we just never will. For the physical part, I guess just try to take our diets more serious, lay off the drink, drugs, and smoking. I'm working on that smoking part.
And something else we should already know but some people forget is to not get into situations that we cannot easily get out of. At our age those things would be don't get in trouble with the law, don't take on any new chemical addictions, don't get pregnant nor married just because time is running low or some crap, and whatever