I'm not all that familiar with calculating jump force but, based on a video of an adult man jumping with the force exerted being measured by a pressure plate, it took roughly 2000 newtons to jump a little over 2.5 feet. Assuming she weighs about the same as that guy with her full armor and sword, she would exert more than 22 kN of force to jump 30 feet, which is more than 2200kg of force, but if we count the height of the horse it would probably only be about 25ft so, roughly 20kN and 2000kg of force.