My first bike ride in 40 years, I was 6'2 360lbs and on a $60 pawn shop steel frame Giant Rincon way too small for me. It had a rigid fork, and the front derailleur didn't work at all. I stopped and moved it by hand if I needed to. I didn't ride out of sight my first ride at age 50 before having to get off and walk, but I kept on. Just make sure what you are riding is sturdy enough to be safe and go as far as you can every day. Ride every day, if possible, even if it's a couple miles. Rest well, have a good diet and you will get fit and able to go farther over time. It doesn't take 10 rides though or even 50 to make a drastic change. It takes hundreds. By my second-year riding just by cycling every day and good diet, I lost 180 lbs. I rode 360 days my second year averaging just 100 miles a week. that's not much if you do short rides every day and a bit more on the weekends.