| If you're already up to 10 miles on long runs, you should be in good shape to prep for April 2nd. I used a long and drawn out preparation of around 7 months to get me ready for that first one last year, I hit 10 miles on a long run in September and edged my way up to doing 13.1 miles 2 weeks before the half-marathon. But lots of half-marathon training plans only go up to 10 miles on the long runs. I just found it useful and reassuring to my own mind to have done the 13.1 and firm up my confidence that I had gotten a good enough sense and theoretical model of how to handle to my insulin, food intake, and activity.
Just try to keep track of your numbers and monitor the effects on the blood sugars.
Even now, almost 3 months after doing my first one, I still get kind of blown away thinking of how I felt when I came around the last curve of the circle in front of the Philadelphia Art Museum. One of the best feelings I've ever known in my life. | 
