I ran three half marathons in 4 months this winter. It got less painful with each one, but I remind myself about mile 10 each time not to get my Red Bull "wings" and think that I ever want to do a full. It's just not me. I am still learning to control my mind to allow me to run such long distances. It's never my body that gives up, it's my brain.
Good luck, whatever decision you make will be the one that's right for you!