Trying to get a canter from Gypsy

Yesterday I worked with Gypsy again in the paddock and in the round pen. I started with the 7 games, including more sideways without a fence (she's starting to get pretty good at this!). Then I took her into the round pen to see if being in there would help her to pick up a canter. We started with just doing walk-trot transitions on line along with changing direction, then I tried to get her to canter. I used slow deliberate swings of my carrot-stick and string in zone 5 repeatedly until she picked up a canter. Also, I had taken her line off to give her some more freedom. Except for a couple of disunited strides, she really couldn't do it. She kept trotting faster and faster (above) and all I really succeeded in doing was scaring the crap out of her. She wouldn't turn into me after that and kept crowding the gate clearly wanting to get away from me - the crazy woman with the stick. I never touched her with the stick or string, but it was too much pressure and it was obvious she couldn't (or wouldn't??) canter. The few strides she did pick up where really choppy and short. Not sure why she couldn't canter. I know she can (I've seen her!). Maybe she's just a really long horse and needs more space? (at least until she's capable of being more collected). She's also really "downhill" (I used 3 large shims when I rode her last and the saddle was still tipped forward), so not sure there's a discomfort factor involved or not?? I don't know. I wish I knew what it was so I could do something about it. Just not sure where to go from here with the cantering.

Anyway, we carried on with the session because I wanted her to calm down and finish on a positive note. So we abandoned cantering and started working on the walk-trot transitions on line. Once I had her doing that a bit more calmly, I decided to try doing some of the change-direction at liberty, which is much easier to do in a round pen! (remaining photos). She did really really well with the changing direction at liberty. She was really focussed on me. Except for a couple of out-turns when I wanted her to turn in to me, she responded very well. The only trouble after that was that I actually asked for too many changes of direction, so when I wanted her to keep trotting around me, she would stop behind me and come in or change direction on her own. So then I had to try to keep her on a circle in one direction. That took some doing. Just about every 3rd or 4th stride, she'd turn in asking "do you want me to turn now? how about now?...." Loved that she was asking me questions all the time and, OH BOY, I got to practice my send over and over! :-) The session turned out really well in the end. I'm glad I was able to settle her down and get her to trust me again. These horses really are the most amazing animals. And I love this one, in particular, a great deal! :-)