I can guarantee that all those tired... and any good feelings... will sooner or later surrender to no feelings whatsoever. Hopefully... that will be decades from today. I entered my exercise program (mostly I just enjoy cycling) shortly after I retired (early) at about your age.

I had my 1st annual check-up when I took up cycling. I also bought a heart monitoring watch, and a bathroom scale that can measure my bodies moisture content.

Many... if not most of us cyclists are old geezers (like myself). Cycling is a great, low impact, and fun way to get outside, sweat, be active, burn a few extra calories, and just enjoy life. But cycling is also serious exercise. Make sure your doctor approves of your new activity. Watch out that your not over doing the exercise. And stay well rested and hydrated as you get into condition.