She's a cute kid and she looks to be having fun so congratulations to you - not sure if you are dad or mom.
Ash pointed out that she has a pause in her prep. She looks like she was coached to take the racket all the way back where it points toward the back fence. Maybe a long term goal might be to have her stop with her racket head up above her hands and between her shoulders and wait there to start her swing. Watch video of Federer and Nadal or Justin Henin on Youtube to see what I mean. They turn shoulders but keep hands still between shoulders with racket head up above hands. Then when they start the swing it is a continuous loop to contact. Federer's smaller loop is ideal in my book.