If you don't feel confident enough to work through it on your own, have someone else ride her for you for a while and have them have you work with them to get the feel of it. If they take out the majority of her bucks and teach you how to reprimand her when she tries again, that might make you feel more confident. Dealing with a bucker isnt fun for beginners or people who havent had experience with it...been there, done that. But she sounds like a great horse. Does she just buck when she's scared? Or does she have a bad tack fit? Teeth? My one mare used to buck because of having stiff joints and bad teeth; once she had more time on her in the "warm up" ring had her teeth done she has been a great horse. Just keep trying, don't give up!