Being by far the senior lady here, I most like Toni's comment about keep moving. Don't let the first two seconds pass with inactivity. That said, of course, I procrastinate. Part of the human condition. And I agree that not putting off things is a good strategy.
However, I don't agree that you should give up dreams. You may not be able to accomplish some things in the way you envisioned but that doesn't necessarily mean is cannot be done another way. Ride a motorcycle? Well, if two wheelers don't work, get a trike! There are some pretty spiffy ones on the market. Fly an airplane? There may be health restrictions, but age isn't one of them for the license. Take lessons. You are flying, just not alone and you may astonished yourself with what you are able to do. Wanna do CNC? Good! Lots of kits out there and they WILL keep your brain engaged!
The brain has to play for the body to be healthy. So give it some toys and full steam ahead! Did you notice that procrastination is less likely to occur when you are having fun? And everything in moderation. Good food, some exercise, enough sleep, something to tantalize the brain plus a positive attitude equals a fun life. This from one of the seniors here.
Good friend from many years ago (now deceased) once asked me what were some of my 'somedays.' I replied, "What's a 'someday'?" He said, "You know, someday I am gonna to this or that." One of mine was flying. BTDT. Huge fun. Other interests now. Another was riding a motorcycle. BTDT twice. Also huge fun. Now in my seventies, have decided riding a motorcycle is this crazy traffic is silly. Getting back into CNC because there is an itch and I like to make things. Building a house because the opportunity is here and I have always wanted to. Working a day job I love in spite of many in authority said I couldn't. Not good words to wave in front of me!
I don't do any of those things like I would if I were in my thirties. How could I enjoy the age I am if I yearn for a different age?
Go for it, whatever it is. Burnin' sunlight here! Think from a John Wayne movie.