Thanks for your service. Keep a close eye on that aorta. Your docs should be doing annual or twice-annual CT scans of it to watch its growth. You're a likely candidate for surgery at 5.0cm but it will depend on your age, size, and its rate of progression. Find the best imaging lab in your state and use it consistently. For you, that's probably the VA but make sure to continue pushing for surveillance scans at least every year (if not 6 months). Peace.