I did it!
I was lucky enough to have the fitness room to myself last night after work, so I wasn't even remotely shy.
Week One involves a 5-minute warm up, and then intervals of 60 seconds of jogging or running and 90 seconds of walking. I did the intervals for the prescribed 20 minutes, then did a 5-minute cool down and a stretch.
I kept a reasonable pace of jogging and walking intervals, but I didn't over-do it. I can even walk this morning. Yay for me!
Someday soon, I'll be that fit, spunky girl running by the river, through the countryside, around medieval cities in Europe (when I go to Germany in June), along the beach. Hotness ensues.