HF: I'm going to temper my encouragement with a word of caution. Are you sure you want to jump from a 10K to a full marathon without doing one or two 20Ks or half marathons first? I'm not speaking from experience as I have done some HMs but have no desire to do a full marathon. Regardless of the distance, 13.1 or 26.2, your body will be stressed far more than in a 10K and you must train it over a period of several months with small incremental increases in distance (hence my suggestion to do some HMs first). If you don't ramp up slowly and include ample rest days, you can almost guarantee yourself some sort of injury. Jeff Galloway has a monthly column in Runners World magazine for beginners. He stresses the run/walk approach and I strongly urge you to follow it.
At 15 miles average per week, you would get new shoes at 26-27 weeks, so your timetable seems right to me. Ask your running store to be sure.
--Steve
Completed in 2012:
The Qualifier HM, Midland MI, May 2012, 2:58, 80+ degrees
Dam to Dam 20K, Des Moines, IA, June 2012, 2:17, PR for this race
Garry Bjorklund HM, Duluth, MN, June 2012, 2:20
Fox Valley HM, St. Charles, IL, 9/16/12, 2:23
Des Moines HM, 10/21/12, 2:19
Tentative plans for 2013:
Wisconsin (Half) Marathon, Kenosha, WI 5/4/2013 (registered)
Dam To Dam 20K, Des Moines, 6/2/2013 (registration opens March 20th)
Grandma's (Half) Marathon, Duluth, MN, 6/22/2013 (if I get picked again in the lottery)
Des Moines HM, 10/20/2013 (registered)