Decent story but laughably unbelieavble

So at the kid's birthday party, we learn that Ronnie is a tough kid who takes not s**t from anyone. She calls a girl a b**ch to her face and she punches an adult! Ronnie is a badass! Then, 10 minutes later, Ronnie is taking orders from fat Alice and doing everything she says? This change in Ronnie made NO sense whatsoever. Portray her as naive throughout perhaps, but don't set her up as an independent and though...and THEN suddenly turn her naive with no warning.
A mother who frames her own 11-year-old daughter for murder?
A cop who asks all her questions 7 years after the crime. As if no one at the time had already grilled both girls.
A kidnapping in a public store in broad daylight goes unnoticed?
Can a parent just forgive a statutory rape and refuse to press charges...or doesn't the state automatically prosecute rapists?
And how does a convicted murderer 15-year-old in a public institution hide her pregnancy from the cops?
The cliched characters in this are so unoriginal, it detracts from the film....Like Elizabeth Banks' husband telling her she's working too hard. Why even have him in the movie? Or Ronnie coming from a white-trashy arguing mom and dad. Or the pimp-like boyfriend berating his woman in public.