I am terrified that my heart will stop or my aorta will burst, can't stop this fear, I got bav and 45mm dilated aortic root. Please reassure me.?

Bicuspid AV. Don't be terrified! but do follow-up with a cardiologist on a regular basis. This will require definitive surgical treatment at some point.
Bicuspid aortic valv. You are at risk for aortic dissection but forewarned is forearmed. You will need an aortic valve replacement and aortic root reconstruction but timing is everything. You obviously are established with a cardiologist. Get an annual echo and stay in touch with your doc. I follow lots of folks just like you and have never lost 1. When you get to 50 mm, you should see a ct surgeon. This is routine.