Most physical things are use it or lose it, so don't slow down, move around, have sex, dance, lift weights and definitely do yoga but:
The one physical effect I've suffered getting older is that it takes for fucking ever to heal or recover. So don't neglect rest and recovery either. Especially with lifting, every other day may work better now.
Don't get old too soon, because then if you live a long time, you might be old for decades, wait until you are closer to the end to get old.
Most of all - enjoy! Enjoy life, now you have more experience and can feel it more. Like really look around at all the amazing things in the world. Even now. So much beauty, so much joy.
My (now deceased) grandpa could probably still show my dad a thing or two in regards to strength at the time he was alive.
Afaik he trained GSD for police duty.
My still alive grandpa though becoming old still tendes to his garden.
I'm 56F and honestly stronger than I've ever been, but slower OMG, can't run fast or jump but can stand on my hands, do pushups, all sorts of things I couldn't do when younger. Strength training is also important because strong muscles make stronger bones.