I do believe in round pen working. I have broke several young horses who never bucked with it. It you don't have a round pen then make one up or rope off a section or a corral. Don't make it too big that she can pull away from you. Use a long lunge line and get her use to going in small circles around you first. Then as she get use to that then increase the size of the circle. a whip is only to encourage them to move and not to whip them with. Have her run circles around you until she gets tired and then try to do new things with her. A round pen work is safer for you, then just throwing a saddle on her and trying to ride her. If you have a old jumpsuit or overalls stuff it with sand and hay, then use them as a first rider. Tie the suit to the saddle so it will not fall off if she should start to buck when you ask her to move around. As she accepts the stuffed suit rider without bucking then you progress to someone sitting on her and leading her around. She will lead that nothing you are doing to her or asking her to do will hurt her. If she bucks or jumps then continue to ask her to run until she tires out some more. She will learn that her lungs hurt worse than anything you are doing to her. I learned theses things from a personal horse trainer and Parelli