Completed the last run of the program tonight and feel great! I started out with the intention of completing the run in my fastest ever time and I did it! No world records, but 5k in just over 31 minutes is a personal best, and at 53 and not having run since school I don't think that's too bad.
To anyone thinking of starting this program, or those wavering around the middle weeks, you can do it! I went from relative inactivity to running 30 minutes three times a week because of this. It really does work.