Please someone tell me it's all quite normal. Our daughter has never wanted for nothing, holidays, money, food,shelter everything. She was wonderful, the perfect girl until he started high school. ok so expected some change but to go from a funny bright helpful girl into an obnoxious sullen argumentative Alien over night aaaarrrgghhh why. She is 15 nearly 16, loud crass, screams and yells like a spoilt brat. We are trying to remain calm but really want to jump on her sometimes as she is tearing the household apart. Anyone else got this problem I need help on how to cope before I lose it completely.