Shes a 7 month old Australian Shepherd with quite a mouth on her. She has a very high energy level but we do walk her and play with her daily, but she still feels the need to just sit there and bark at us and whine without any noticeable reason. She also thinks of my daughter (who is 15) as another puppy, but is rather rough with her, such as biting, and does not have any respect or listen to her.
Whats going on here?

Edit : We do walk her twice daily for about 45 mins in the morning, and the same at night, as well as playing in between.