I did it! I ran my third half marathon in April and soon after started training for a full marathon. I followed a great training program and this past Sunday, I ran the Marine Corps Marathon! It was an amazing sense of accomplishment! I'm still super sore, but still feeling great about it.
I've always wanted to run a marathon myself but I have a love/hate relationship with running. It seems to me like it's more about the sense of accomplishment at the end, however, than whether or not you're passionate about running. I know tons of people who've run marathons who aren't "runners," so it's very inspiring. Do you think you'll do one again?
I definitely recommend checking out Team in Training (link above) -- it turns the training until a real community experience and makes the race about more than just you, by raising money for the Leukemia/Lymphoma Society. A friend of mine who is 34 just beat Lymphoma -- reminding me just how important that cause is. So, while I actually did not join T and T b/c it wasn't as convenient for me while I was in between homes, I highly recommend it based on everyone I know who has done it and loved it.
Congratulations! There is nothing quite like that first marathon. There are many group training programs other than TnT (with whom I've been involved with on and off for over a decade). TnT is the most well-known, but I recommend choosing one with whose cause you feel a connection. There are loads to choose from. Good luck and happy running!