I have been trying half seat canter with her allot, she feels very weird at the canter. Its not a gentle rolling motion no matter how sow she goes it feels very unbalanced like she's throwing her feet down. I don't think im used to her canter because I typically ride large horses with a big stride and even my pinto has a balanced long strided slow canter.
Last time I talked to my dressage trainer about it she laughed it off and tried to make me feel better saying something along the lines of "riding green horses is like learning to ride all over again". And how she gets embarrassed riding baby's at her farm. (younger untrained horses)
One day I will feel natural on top of Tessa
Also, horses typically put more weight on their front legs. It's always a good thing to encourage them to shift their weight evenly on their back legs. What this does is it makes the ride smoother, makes them more steerable, and helps the get their striding. One of the easiest ways to get your horse to do this is to back her up a few steps. When she shifts her weight, it should almost feel like her entire back rises up a little higher. This is also known as her 'giving you her back'. It may help you a lot with her canter.
That's as much as I know on that topic. If you want to know more you could start a new thread asking about it, because I'm sure there are many many MANY much more knowlageable people on this forum.