Recently I read that close to the battle of Hastings 1066, men were called to serve in fyrd up to 60 years old. What would someone of this age do to help the army? I can't imagine they would be fighting alongside other much younger men.
Old men (40-50) fight in Battle of the Nations, and do as well, if not better than the younger guys. If you're wanting to see the closest thing to medieval battles, and the people involved, then that's where you'll want to look.
You'd be surprised.
Raymond IV of Toulouse was around 55 when he went on the First Crusade.
Sir John Talbot was at least 66 when he commanded the English during the Battle of Castillon.
Jean Parisot de la Valette, Grand Master of the Knights Hospitallier was 69 when he led the Knights during the Great Siege of Malta.