If the white spot suspected of being a saddle rub was there when you got her, it isn't necessarily your saddle doing it... but yes, it's always good to make sure your saddle fits well.
I'm not a conformation pro either, but she looks fairly good to me. The only things are, she looks a little on the chubby side (that can be remedied fortunately) and her hooves seem remarkably small for the rest of her body.
I like her...she has a very kind look to her. She looks a little tubby, but that may the fuzzies on her too. Her legs look nice and sturdy, and I like her compact build! Her feet do look a little small, but they also look like they were freshly trimmed, so I wouldn't think too much of it. She is a cutie :)