You will start feeling younger when you start putting miles on that bicycle.
Lots of us in our 60's (I am 65) 70's and even 80's ride high tech road and recumbents.
Enjoy and get out there and ride. You can ride easily in temps of 45+ fahrenheit even with wind with proper layers of clothing. I know, I did 20 miles yesterday at 46F and winds of 10-15 mph.
Welcome. I didn't start serious bicycling until I was 58, so you are right in there with the rest of us.