So there's this TB mare that is fresh. She's been started perfectly from the ground -- sacked out, not spooky, longes, takes the bit, takes the saddle, and acts like a dead broke horse... from the ground. Then, you go to get on her, and she will jump away and sometimes kick out. She has never been ridden successfully, mind you. The few times she HAS been ridden have resulted in hard falls from her bucking frantically. She's a very sweet mare otherwise. What to do, what to do?! Did I mention she's 17 hands?