Your BP is normal. No need to evaluate the 55. No need to be concerned. If you have A-fib, you should see a cardiologist regularly. I wonder if you need anti-coagulation drugs to prevent stroke. You should consult your doctor for further advice.
Your blood pressure is not that bad. You do not have to elevate the 55. With aging, the blood vessels get stiff and the pulse pressure (systolic pressure minus diastolic pressure) gets larger. Your BP represents a typical BP in an elderly. At present, you do not need to do anything.