Great story! I am in a similar spot. Just started riding in late April and am planning to do my first centruy on 9/1. I didn't get the "bad news" healthwise, but I was definitely out of shape and over weight (still am, but by less now...). Keep on peddlin' bro!!
Oh, btw, my longest ride to date is 77 mi. The worst part about the ride was my hands. I leanred two things from that ride. Need to do something about those hands and I need to learn to pace myself better (did about 17 mph for the first 44 miles and started crashing at about mile 70). I have a flat bar road bike (now wish I didn't). I just got some new Ergon grips put on and a computer so I can watch my pace. I am planning a 50 mile, paced, ride this weekend. We will see how these things work for me. Hopefully it will help me complete the century.
Great post!!