Big Girls Don't Cry... They Get Even (1991)

Laura's parents divorced when she was eight. Now, at thirteen, she lives with her mother, her stepfather, two stepbrothers, a stepsister, and a half-brother. She used to visit her father, stepmother (third stepmother) and half-sister, but now *another* divorce is in the works, so Laura visits her father and his pregnant girlfriend -- who's only six years older than she is. Who should she feel loyalty to? And is it any wonder she wants to run away from home?