I gotta say, "I'll take D, from Dreamcatcher's list."
You are not experienced enough to master this horse...yet. It's expensive to start hiring a trainer bc your instructor expects you handle your horse without instruction--there's no logic to this.
Ask your instructor to find you a buyer.
Ask your friends to help you horse-shop for a horse with better training.
Getting hurt by this horse will discourage your future horse pursuits.
When you buy your next GOOD horse--may I suggest buying a middle-aged, safe lesson horse?--shop for a new trainer, who respects you and the money you pay her.
I had an OTTB with problems, and I kept him from age 8 to age 16. He'd sit down with DH on his back, we've had to lunge him in tight circles before using him--the list goes on...
Finally, he slipped on the ice and threw out his back fighting with another member of the herd. My Vet suggested a chiropractor. I suggested an auction and sold him to the meat market. WHY? Bc I didn't want to sell this pretty, 16'2hh black TB, who jumped easily, and had some dressage training despite his bad manners to a 15yo, LIKE YOU, and wonder when she would get hurt. Somebody's sold you their problem horse, and it is inappropriate to expect you to handle this.
P.S. This happens a lot nowadays.
I respectfully disagree Corporal
In some cases, I seriously see your point. Lots of people get in WAY over their heads and need to sell. BUT I do not think this is one of these cases.
I do not think this horse is dangerous, judging from her previous posts. And with that I will say there is no such thing as a bomb proof, perfect horse
!!! EVERY horse has quirks and problems. There are no dead broke horses, there are only well trained (and well tempered) horses handled by well trained horsemen.
What I am trying to say is that it doesn't matter what horse she has, if she doesn't teach it respect and have someone to help her, she will get taken advantage of by the horse. You can buy a 30 year old, "dead broke" half dead horse, and it will still most likely tell her to buzz off. She needs to train herself, or have someone train her, and I am fairly confident that the horse will follow suit, especially given the information she has provided (horse did listen well when bought, did lead and ride just fine). He changed after she bought him and he has taken advantage of her. It is a problem with the person, not the horse.
PS. OP, do not take offense to that, everyone needs to learn, but it is not your horse who has a problem, it is just you needing some guidance and learning, as everyone needs at some point