I have a stepdaughter she's 15yrs old. It's been a year now my problem with her is that when I tell her that she must wash dishes or clean her bedroom hell breaks lose. She will be moody and not talk to anyone or sometimes be mean to my daughter which is her stepsister. She always fights with her mom, I've a chat with and told her not fight with her mom and try build a relationship with her, and must stop being nice to her only when she wants things from her.