She's a bit of a sensitive mare from what I can see (as a lot of mares are) so maybe your should ride her carefully and calmly (not lethargic or losing impulsion, just carefully). She showed a bit of resistance in the turn on the haunches, throwing her head around etc. I suggest softening your hand a little and using your legs more to turn her. You should be able to walk a circle without touching the reins, only using your legs. Hopefully this helps a little. Oh, you have a very pretty girl.