I don't think that either of us worry about it. You will gradually get rid of the time bomb feeling. I have a blood dyscrasia (monoclonal gammopathy), which was discovered at Mayo in 2002 when I was 59 years old. I suspect that I had it stemming from a ruptured appendix with sepsis in 2000. For years I worried about it and my heart stopped every time I had blood drawn. My hematologist ordered my blood drawn every three months. It was justified because my dad had a cancer that had probably evolved from a similar blood dyscrasia and I had a cousin with a very aggressive AML. Now I don't worry about it. I have a different hematologist, who is not worried either and that makes a big difference; the previous one retired.
You may never have a problem if you behave yourself and keep your blood pressure low and don't lift weights or lift other things that could cause stress.
My husband is reasonably "good" and both we and his current thoracic surgeon (as well as his cardiologist) are of the opinion that he will die of something else. Time will tell.
My husband's first cousin had an ascending aortic aneurysm (MIDLEVEL also) and his dissected about the same time as my husband's was detected on the echo. He died a couple of times before he was "put back together." He also has a descending aortic aneurysm and an abdominal aneurysm, He is almost exactly the same age as my husband (one month difference). So this is probably hereditary. This cousin was a weight lifter but also had a healthy very athletically active life style. If one of his aneurysms ruptures, he just wants to die. My husband would not want to die -- and that is a very good thing.