I can kind if imagine how that would go. I bet she starts trotting faster and faster which causes you to maybe lean forward a bit, 'cause it's hard to stay with that kind of a rushing trot. And of course, that only encourages her to rush more. Been there, done that.
Being as young as she is, she may need to move out a bit, so if you can, and you're in an arena which is enclosed and safer, you might let her move out a bit, for awhile. If she starts to get too wacky , work her in a smaller cirlce but not actually one rein stopping. Let her go for a bit in a smaller circle and try to keep your body kind of heavy and "slow", to encourage her to slow, When she does, you let her out of the smaller circle and see if she will hold a nice trot on a bigger cirlce (like the whole arena). If she starts rushing, go back into the smaller circle til she offers a slower gait.
I think doing the one rein stop constantly might be just making her really frustrated and wanting to work against you all the more.