Due to your lacking of any knowledge of magic and never encountering it, magic won't affect you as long as you do not see it. If you were to be damaged by a spell or be affected by a spell that isn't within your field of vision, you are completely unaffected by it regardless of how powerful it is. Only divine or other greater power magic will work normally, healing will be unaffected as you do have some knowledge of this kind of magic. Those who would cast a spell on you are unaware of this property of yours until they have already casted their spell. Closing your eyes has no effect on this ability.