How do I get my pony to listen instead of getting strong?

Hi! One thing you can do is hand the responsibility for holding the pace you ask for back to your pony, by riding on a loose rein and only intervening when you must. In other words, keep giving a loose rein throughout. Set out cones in a circle of roughly 15-20 m across. Ride the circle on a loose rein and only intervene briefly to turn, leading with the rein and giving the rein away the moment the pony turns. The focus is on following the circle. If you need to slow down, start with your seat and then ask briefly with the reins until the pace has come down, then give the rein away straight away. You leave the responsibility for line and pace to the pony but intervene when you need to. Be patient and do not give up. It can be hard going before the pony starts to understand what you want.

Start in walk, then trot, and canter last. Repeat every day for a while. Keep the goal in mind, that the horse should hold its line and pace without rein contact. Once this is working, you can begin riding on a soft contact, and always return to the exercise if she gets strong again. Good luck!