Serious Aortic valve stenosis. Operated with new bio valve. Short of breath on climbing. Do I need to have the surgery again?

I was quite fit with no symptom of any kind, except that I use to breath heavily on climbing steps. On a regular medical checkup, my house doctor found that he heard some strange sound from the heart but was not quite sure. I was recommended to a heart specialist who diagnosed me to be having serious heart problem. Serious Aortic valve stenosis. He also said if not operated I may live for another four years or so. This was quite scary. I decided to get operated with a new bio valve. I recovered very well and after just six months everything was like it was before! meaning, I did not feel any difference. Now three yeas after the surgery, the only problem I feel is short of breath climbing a few steps. It was the only symptom I had before the op and I still have it but I think it is getting worst. I am quite scared if I will have to under go another open heart surgery. I am sixty years young and in very good shape. I do regular exercise and play badminton twice a week with guys much younger than myself. Please advice.