9 miles at 15 mph was a "good" ride for me (at the time 50 lbs overweight, an ex-pack-a-day-smoker, and high BP) when I got back to cycling by commuting to work 7 years ago. Just stick with it and try to ride 4-5 days a week, adding a little bit more distance and speed each week. Those 50 lbs melted away after 2 years, and a couple more years after that I was doing 19 mph 100 mile rides, and ultimately 200 and 300 mile rides, but those may require you to be a little insane.
Last edited by Riveting; 07-09-19 at 05:04 PM.