Sounds like it might be a suck it and see. I suppose I can always defer my entry in March until 2014 if the training is not going well. I've only been running a year and so far only a 10k and 1/2 marathon under my belt. Although might try another half between now and december.
I have just completed my first half marathon (1:55:52) and have a place for London Marathon 2013...unfortunately surgery means I will be unable to run from 10th Dec 2012 to 21st Jan 2013 which is exactly 3 months to the big day. I'll be training up to 10th Dec increasing distance as I go...will the 3 months be enough...I want a sub 4:30 time.