There are a number of ways to approach it and if you are unable to get her to a round pen then doing what you are will work. I would also suggest that she goes back to a stall or a smaller pen where she is easier to work with and doesn't have a ton of room to run. The only thing I suggest is don't try to break a bad habit by creating a new one. It is okay to feed her treats but don't due it from your hand, find a little feed bucket to use. Otherwise you are going to get a mouthy horse especailly since she is a young horse. You don't want her constantly looking for treats on you and nibbling around on you. Crowding up in your space. It may be cute at first, but the first time she bites someone because she thinks they or you have a treat she could due some serious damage.

Good luck with her, and get her to a round pen for a little work, soon she will figure out that it is better to stand for the halter than run around.