Hello, I think running a marathon is a great goal. I began my running journey Dec 2012, with a group called Black Girls Run, and have been hooked since, I just ran my first half marathon May 5, 2013 and felt so accomplished. Initially, my goal was to simply run a 5k and I am a proud 1/2 marathon runner, I ran 13.1 miles in 2:35 hours. So yes you can do it!!! I was banded Oct. 2010, weighed in at 250ish and as of today, I weigh 140. Also, between that time, I had a baby Oct. 8, 2011;)