I've run 2 marathons and I am not going to lie, carrying 200+ for 26.2 miles is going to hurt.. The biggest hurdle is to stay healthy enough and put enough quality miles in so you can enjoy the experience.. what kind of mile times are you running right now?

See how you do with your 1/2 marathon before to go all in for the marathon, it is hard on your body..

My first marathon, my longest training run was 16 miles.. I would recommend a medium pace 20 mile training run just so your body acclimate's enough before doing the whole 26.2..