Playground Etiquette

We are playing on this playground, water thing and an older boy pushes Ben off of a piece of playground equipment. Gormah, who was close by, charges up to this boy. She has her hands raised and I am certain she is going to push him back. She gets in this boy's face (never pushes him although I know she wants to. Hell, I want to) and screams "DO NOT PUSH MY BROTHER!". She starts to walk away and turns back to him and screams "PLEASE!".
She then lopes up to me like a proud puppy, who has just killed a rabbit, and is laying the carcus at your feet as if it is the greatest gift in the world. Her eyes are proud and she is excited to tell me how she saved Ben. She is all legs and her eyes are sparkling.
After she tells me, I hug her and tell her thanks for taking care of her brother. Now I know she should not have yelled and I should have intervened but her reaction was exactly how I wanted to respond and could never get away with. She did not push even though the urge was there AND she said please. I know I have the emotional maturity of a seven-year old but I was proud of her.