First of all, good luck!
Which measurement is the length and which the diameter?
When I was getting worked up for my aortic valve replacement, the surgeon mentioned that my aorta was dilated to just below the point at which they would do something. He also said that the store bought valve installation would tighten it up a little.
At our age, going to the hospital is like stopping into the supermarket for a loaf of bread, and coming out with a full cart.