My concern is that in the photos she looks... irritated. And in the first photo it looks like you're goosing her with your heel. If she was used for mounted games she is probably very sensitive to the aids and as a new rider you may be inadvertently pushing some buttons without realizing it.
If you can get some more formal lessons and some extra help from friends that would be great. She is a dead cute little mare and seems to be kind and willing, however, I think there's the potential for you to get into more trouble than you know how to get out of.
Keep posting and let us know how it's going!