So despite my intention of keeping track of how many minutes/hours I spent actually reading, I failed at keeping track after about a half hour. Oops.
Well, we're into hour 6 and I've finished my first book. I'm Half-Sick of Shadows by Alan Bradley, which I loved. Hopefully, I'll get another book or two done before the readathon ends but with this one done, I now consider the readathon to be a success!