Start by walking over poles and teeny jumps, and get someone to help you on the ground - little and often and don't move on until she is completely relaxed with the current stage
Forget about jumping until you have the basics sorted... Your pony has more fundamental issues and once you solve those, the jumping will be easily sorted too. May I ask do you have lessons on your pony? Do you have anyone to help you with handling?
My horse was seriously scared of jumping in the beginning. She was scared of the gap under the poles, the poles being underneath her, and then when she got used to all of that she was scared of fillers. However, now, she isn't scared and she jumps everything.
Get a trainer.
Perseverance, leadership and empathy.
It will help in either case, but if your pony is being naughty you need to get your schooling right so that your pony is sharp off your aids. The pony needs to know that when you put both your legs on the only option is to go forward, and straight. If the pony runs out, work on your leg yields. Make sure you can direct the pony with your legs, and also block the pony so it can't run out.
But anyway, if your pony is nervous, I agree with the above, start with one pole. Do loads of trot poles and canter poles. See if you can get your pony to stand still with the pole underneath her until she relaxes, so she knows it won't hurt her. Then raise it, inch by inch, if she gets scared, make it easier again.
If all else fails, she has the talent and your determined to jump her, send her to a professional rider to get it sorted.