Bottom line, a horse should not be crowding your space like that, and it's not your responsibility to school this horse. Her behavior is dangerous, and not just because of your age and joint issues that you mentioned -- she is a safety hazard to anyone on your property who doesn't have a whip, apparently, and she is also a hazard to herself. There are many things found near the outside of the average home that a horse could get into that could really be an issue.
I wouldn't have a horse like that on my property, certainly not running around the entire piece of land with access to your home and personal yard. She either needs to move, or be contained to a smaller space.