I'm sorry, youtube is Banned in my Nation - perhaps a summery would help?
Assuming that she is a product of something like a broken home where violence was the norm - I fear that when things get out of hand the victim gets further victimized by the State.
Most people in prison come from what we euphemistically call 'dysfunctional homes'. Its a nice way to say moderately to severely abusive families. There is a culture of violence which begets more violence, its a never ending cycle and society's answer is punishment for 'crimes'.
Being from a 'dysfunctional family' I know the drives and motivations to want to kill a person just to end the nightmare that is them. I also get the whole 'turning to a life of crime' in order to make ends meet, or to get your jollies. I sold drugs for the longest time to support my self destructive drug habit. I used drugs because I was self-medicating a plethora of mental/emotional health issues largely due to being beaten, sexually assaulted, mentally and emotionally abused and/or neglected.
Having been to many 'support groups' and 'group therapy' for 'crap' I have heard the same story being told over and over and over again.
"I was raised in a violent/broken home situation, grew up and was forced to survive so I did what was necessary to survive with what I had learned at home."
I suspect that around 5-8% of criminals behind bars are actually criminals - meaning willfully, disobedient - I suspect that the majority have mental/emotional health issues and turned to what they know in order to survive life.
If you hear of a criminals record and your gut reaction is 'that's crazy'... well it is crazy and perhaps instead of punishing them we need to treat their mental illness(es)?
I will go out on a limb her and say that a 16 year old girl killing someone is an act of an unstable mind - a person who was insane, thus she should be treated/rehabilitated as best as possible and not thrown behind bars and locked up like an animal.
Basically, a 43 year old man picked her up as a prostitute when she was 16 and as he leaned over to his bedside drawer, she thought that he was reaching for a gun, and she freaked out and shot him to death.
She got life imprisonment. There's this one part at around 34:00 in, where she makes this incredible insight about all the men who have treated her badly in her life.
Poor scared girl, 16, being used for sex, terrified of the man she is with... Granted murder is a bit of an extreme reaction... but still she was put in this mind set by a lot of ugly.