Don’t panic but stay vigilant. Mine was found by accident too. It was 4 cm. At 4.5 I have an emergency double dissection. That was two years ago. Find a cardiologist or vascular Doctor that you trust and believe in. In the mean time (had I known) don’t lift anything that causes you to grunt or groan, hold your breath, or that you couldn’t lift push or pull repetitively. And work on keeping your blood pressure down until you get under a doctor’s care. And walk, walk, walk, as much as you can tolerate - don’t push it just a casual walk. Then when you get a doc, listen to them. Normally they don’t get too excited, unfortunately. Best wishes.