My neices have seen a couple of episodes but as they live about seven hours from where I live I never got to see them often enough to show many of the epsidoes. They did say they liked it though. I can't remember if they were 7 (probably closer to 8 or 10). When one of my nephews was 6 when he saw it for the first time (The Pilot). He really jumped when the Hulk punched through the chamber window. He also asked if the Hulk was going to hurt the girl or her dad by the lake. I just had to remind him that the Hulk is a good guy. By the end though, he could see how sensitive he is. I think if you're watching it with her, that is key. You can always stop the DVD if she seems scared. Of course, you should only show it to her if your sister allows it.