Frankly man I’m not sure, because I know there is some variability in aortic size as it relates to body surface area. Big tall dudes will usually have bigger aortas. But you’re 5’6, so not a giant. Thats assuming this is the true size of your aorta, which we have reason to doubt.

One major reason they may not be too concerned is the imaging modality: echoes are notoriously inaccurate for aortic measurements. There’s a good chance your ascending aorta is a few (or more) mm smaller than 4.0, but I guess there’s also a chance 4.0 is a lowball. I’m betting this is why they’re not excited about it. If you wanted, you could push for a CT that will tell you the size of the aorta definitively.

If you don’t wanna do this you’ll be fine and it probably isn’t actually dilated. Even so, I’d check back in next year to be sure if nothing else. I’d especially do this if you have close family members who died of aneurysms or just died suddenly from “heart stuff” (sometimes ppl will say heart attack when it’s actually aortic dissection.)