I'm not a horse owner or anything and she may just be being obstinate for no reason, but have you had her checked by a vet? She may have problem that makes it painful to be ridden, so she's avoiding the halter...idk. My dog hated his old harness and finally we realized it was chafing him...
I don't have any horses but I live near Hanover Shoe Farms. I love driving past, esp in the morning because it's so pretty! I have ridden a few times at camp and with friends. I would love to learn but def don't have the money😟