So I am pretty sure I over watered my cactus because it is yellowing at the base. Now I know how I am suppose to water it. However, should I cut off the base of the plant where it is yellow, which I am sure will destroy the plant? Should I just leave it alone and see what it does?
You will not be able to cut off the Barrel Cactus and repot.
You are in a wait and see phase.
Try not to stress and remember that a plant loss happens and gives you the opportunity to learn and go plant shopping!