Welcome to the forum!
If you feel better now wait till you hit 65-70!
When you first start using the exercise bike it will be your worst enemy. You will approach it with dread and loathing.
Keep at it though because it will deliver you great results. Just remember to build up your speed and endurance slowly. My wife was on the bike last night and only managed 5 or so minutes at a slow pace. I did three lots of 30 minutes at a good rate of knots burning around 1,500 calories. When I started using the exercise bike I'm sure that my wife could have beaten me easily.
You must feel great getting out of the triple digits and into double digits. Good work on losing the 13 kilos. How long have you been going at it?
Wishing you continued success for a better future