Happy birthday to you and lolsociety. You two share a birthday with my sister. I too have downloaded the app and plan on using it to train for a 1/2 marathon I'm running in October. I'm in awful shape. I was using Fitnesspal but fell away from it as life/stress wore me down. Time to "man-up" as they say.
If you commit to run a couple times a week, you'll build up the endurance quicker than you might think. You might even get addicted; in which case I'd recommend buying a decent bicycle as it's all the joy with zero dread, for me. :) For running, check out the couch to 5k regimine if you haven't already,
It's not my first 1/2, I've been an avid runner in the past and I know I can get back up to speed relatively quickly, it's just taking those first few runs that's difficult. In fact, the very first Hubski podcast I made was titled "Running Sucks" -check it out. Now, biking I've never really gotten in to. I have a decent bike though, I should do it!