I agree with both Kay and Jenn. Ignore her, and walk away. All that matters is that you love Nova, not your sister. I know how it is not being able to let your dog off the leash. If we did that with Alex, in 5 seconds, he'd be out of our sight. He has a very good sense of smell, and since one of his breeds is a sheep guarder, he tracks smells and things. He'll try to go out the door when you leave, just because he loves to go so much. I know that Nova is a wonderful dog, and that you love her and she loves you. Don't listen to what your sister says, Nova is perfect for you.