Hi!! I own a 3 year old Mustang Mare. She is great on the ground and has had tons of groundwork done with her. She even ground ties. The problem though is when we ride in the open field/open areas. We can walk out there fine, but when I ask for the trot, her whole body starts moving sideways and she throws her head. When I ask for the turn it is worse. She will run sideways and just not turn. She ignores my leg and crop. Her teeth are fine/saddle is fine. I just don't know what to do. Any advice?