There is no ‘later’ when it comes to keeping your body in shape.
You are either building it up, or it is breaking down. It doesn’t ‘just stay the same’.
I’ll tell you what happens if you try to do it later.
At first, later is just tomorrow, or another day this week. But that quickly becomes ‘when I’m less busy at work’ or even ‘when my kids go to college’. There are all sorts of ways you can delay this in your head.
No matter what decade you are in, there is always something you are losing that you can’t get back. Yes, it’s a little bit less imperative the younger you are, but it’s not a free pass. Whether it’s range of motion, foundational strength, or flexibility, something is disappearing when it’s not being used or tested.
And the older you are the more that is disappearing, faster, right now, while you’re ‘waiting to get started later’.