I've been on AS and have been very happy with my choice. A good doctor will monitor you pretty closely. If my Gleason goes above 6 I will get treatment. Take the time to do all the research to see if this choice is right for you.
Try to use the experience as a way to motivate yourself to live the healthiest lifestyle possible. I sometimes tell myself that my diagnosis will result in me living longer because it jolted me into watching what I eat, trying to control my stress level and getting proper exercise. Who knows if that's true but positive thinking never hurts.