dd1 is 11 - the youngest in her year 7 class and fundamentally a lovely girl. She has as we would expect grown up a lot since starting her new school in September. Mostly she's just become more independent, less likely to want to do 'babyish' things with her younger siblings etc - all fine. Recently though she's started being very mean to her younger sister (9) and poor dd2 who is a tough cookie is getting really upset. When I've told her off about it dd1 is remorseful and knows what she's doing is wrong, but after a few days she starts again.
It occurred to me today that I read every book going when they were babies and toddlers, but know nothing about this phase. Are there any good books or websites about this stage going into teens? I'm not sure a book about teens would be right just yet.