4 year old girl

I love my little girl but what the heck has happened to her at 4 years old?! We went to see Up today and we all loved it. I would highly recommend seeing this tender movie. I cried thru several parts of it. Brandon is off as Scout camp this week so I just took the 3 boys and Camryn. They were all well behaved during the movie until it was over and they had to go potty. The family restroom was right next to our theatre but each kid had to go in by themselves!! Camryn went in second and she would not get out. I could hear her keep washing her hands and drying them. We banged on the door and she finally unlocked it but would not come out! Darin went in to get her and her monster side came out. She came flying out of the bathroom cussing (not the worst word but close) and was screaming it down the hallways of the theatre. She then took off after Darin and was biting him, punching him, kicking him etc. She became the monster child I never thought I would have. I got down to her level, tried talking to her but she was still mad. I then told her she was going to time out when she got home. You would have thought she would cry but instead told me she was going to run away from home?! I am sure she would have gotten soooo far:) My boys do fight amongst themselves but she is taking it to a whole new level. At least she is well behaved at primary and preschool. My mom claims that I have created her by giving into her too much (which I do, 5th child and I am tired from working nights). She and I are going to have to have some heart to heart talks about what is appropriate behavior and what is not. She did at least apologize to me and went and gave Darin a big hug when we got home. I know there is a blossoming polite girl in there somewhere!!