Hello Michelle! Your question reminds me of the first time I got information on what turned out to be my crucial aortic aneurysm. My mother, an early supporter of alternative medicine, had never allowed me to see a doctor (except for vaccines required to start school) my whole life. At 17, to start college, application rules required you get a routine chest x-ray. The result was given to me via telephone before it was sent off to the University. The result: No TB or other lung problems but "the aorta is somewhat enlarged". My mother and I were totally baffled about the implications (this was long before the Internet). We tried to reason it out and decided that if restricted blood vessels cause heart attacks, then an enlarged blood vessel means, well, you have a very clear blood vessel! (Twenty three years later, another routine xray would show a true pear-shaped aortic aneurysm and show how wrong my mother and I got it.)
You can probably get the info you want off the Internet, but I do not know where you would look. If my memory serves, in general the ascending aorta is about 2 cm across. However, from this list, I have learned that big people can have larger aortas which could be considered normal for them. However, if part of you aorta is in the 2 cm range and parts of it are larger, that indicates some level of aneurysm.
I would guess that you would be put on beta blockers right away to lessen the force of blood coming out of your heart (thus making less stress on you aortic walls). I would further guess you would need frequent MRIs to check how quickly your arteries are growing. The good news for you is that total aortic replacements are done. I have never know anyone who had the whole aorta replaced in one surgery, however. I have a good friend who had her ascending aorta and arch replaced after a (surprise) dissection. Then, a few years later, had the entire descending aorta replaced. What worries me about your account (but I am not a doctor) is that you also have involvement of an artery branching off from your aortic arch. You seem to have some situation(s) causing you to be prone to aneurysms which need some medications (like beta blockers) to be taken for life.
My friend who had her entire aorta replaced is doing well. In her 60s now, she runs a small farm by herself. She especially likes riding around on her small tractor, picking up things with the front shovel. (However, she has observed her strict weight-lifting restrictions--nothing over 25 pounds.) Your life can go on with an artificial aorta if you treat yourself well and get your followup tests.