I Had A Bicuspid Aortic Valve Repair And A Ascending

I had a bicuspid Aortic valve repair and a ascending Aorta Replacement 6 months ago. I feel fine but notice I still get winded after walking on stairs or up hill. I can walk fine on flat ground without any problems. I'm 42 and was wondering if this is typical 6 months out. I feel I lose my legs quickly on steps or hills. I'm I just that out of shape? The doctor said I did have a systolic murmur after surgery but it was probably due to the replaced Aorta. Thoughts?