Been there. You want embarrassingly few miles?
When I restarted in March of 2006, I rode my brand new "old man hybrid bike" home from the LBS. I had to stop halfway to rest. Total distance? 0.65 miles. A little more than half a mile, and I had to stop and rest halfway through that.
It was weeks before I could ride the two miles to work without stopping to rest. But, perseverance pays off. I did my first 50-miler that August and my first metric (100 km, 62.125 mi) that October. Even though I did them in ten-mile increments between rest stops, I did them.
It's dead flat around here, so even expressway overpasses gave me trouble through the following year. I didn't get good at hills until 2008. Twenty-eight months to the day after I first turned a pedal, (and two bikes later) I rode to the top of the highest paved road in North America, Mt. Evans, just west of Denver, CO.
Give it time, and keep turning those pedals.
Now that's inspiring!! Thanks tsl.