Q. I have a Jade plant that has a trunk width of 14 and one half inches.
Jade plants are remarably resilient. A 14-inch plant in a 21-inch pot should be very happy. As long as it is not unstable, I wouldn't worry about the plant. You can selectively prune rather than do heavy pruning to keep it in a good shape. Potting up to a larger pot is also a future option, but I would not be a hurry to do that. Apparently you are following a good watering practice and I would continue that. Over-watering is the bigest risk at this point.