I am a 66 yr old male and my blood test show a RDW-SD of 47.8fl and a RBC of 4.62mil All other CBC readings were normal. Is this a problem?

No. I would check your stool for occult blood in case this is very early iron deficiency perhaps due to a bleeding ulcer or tumor .
Incomplete info. The information you provided about RDW does not add up. However, if rest of the parameters are normal, this is not any thing to be concerned about. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.