I just checked your marathon and saw that it was $60. If that is insignificant to you, then you could register now and decide later whether you were ready.
To be ready, you might need to be running 20-mile long runs by mid January. Could you do that? I can't imagine moving from your current 3 miles to 20 miles that fast, and then to 26 miles a month later!!
Take North's advice, and start training for a future marathon, perhaps New Orleans in 2005.