You never wrote that about your parents spending time with her.
You can't blame me for thinking you spend the most time with her, if you don't.
It's easy to draw the conclusion that your parents are gone a lot, then, leaving you to look after her when all I hear, when you're talking about Lauren, is that you're either defending her at school and nearly getting suspended over it, typical mother-instinct(ive?) behavious.
Taking her to the cinema with your boyfriend, like a young mother would..
Or that you're making her dinner while your parents are gone. Just to name a few examples.
It does seem, to me, like very motherly behaviour.
Maybe it's because I'm older then you are, and make that connection more easily.
Maybe it's because I only had an older brother.
But I'm just saying, that in my opinion, you show motherly behaviour, instead of that of a (big) sister.
That doesn't have to be a bad thing. It can be a very good thing. It just needs to be very clear, for a child, who is who.
Not once they go to school, but from the start. No matter how smart she is, she's a child. You can't tell a child "From now on you'll stop being so attached to Amy and will only listen to us instead". It's like a bird just hatching from an egg. Once they see you as their ..parent.. it's very hard to make that change.
The reason I'm saying this all isn't because I want to be mean, or give you my opinion without knowing what I'm talking about. I know very well what I'm talking about, because I've been in the exact same..well..no.. but a VERY simular situation.
A friend of my mother's, two years ago.. maybe a bit more.
She had a 5 year old daughter, but wasn't a good mother. You could tell.
She ignored her daughter most of the time, still gave her a pacifier (to shut her up?), ..it was a selfish mother.
I've always been good with kids. I felt sorry for the poor girl.
So whenever she was at our place, I'd spend time with her.
Mind you, this friend visited a lot. Too often, if you ask me.
As to not make a too big post, the girl eventually started seeing me as her.. father, you could say. At first, I didn't mind. The kid was happy.
But it began to feel very uncomfortable for me to see the girl ask me if she could please, please stay "here" instead of going home with her mother.
Children, especially those with a nasty experience in their live, get attached to people close to them very fast. That's not only ..ehh... psychologicly..bad., but also dangerous.
I don't want to interfere with how things go at your place, I just want you to see the gravity of the situation. For her sake.