Some people loose it and others don't. Genes I suppose, and taking care of yourself.
I am 44 and think "I still got it".
The best part is that I care less nowadays, don't worry, and see the bigger picture about life in general.

A sense of humor (even dark humor) about getting older is good to have.
It can be pretty funny watching your 6 pack turn into a 1 pack.

It′s all in your head. I′m almost 30 and I′m as young as ever. If you start thinking you′re an old geezer, you′ll become one.

Keep fit, eat healthily, cut out bad habits and addictions.

Become so on top of your game that you cant stop smiling.