I have a god sister of 7 years old who stays with my mom, currently in primary school.

We received complaints from the school where she has to wear safety pants to school, and the topic kind of came up between me and my mom as we were shopping for those. She came to our house as a few weeks old baby, so she practically grew up with us. My family consists mainly of boys, me and my brother, my cousins who are all boys except for 2 girls. So yeah, having her being interested in cars over dolls, building her own pc at the age of 6, and preferring to DIY her small homework table isn't really something I've never seen before whilst growing up with my two female cousins.

The problem is that she simply can't behave like a lady when she's in school. She bullied her classmates in kindergarten, and now she can't sit like a lady in class. I suppose she got that from her jie jies sitting like a boss during our gatherings, that nobody bothers since it's at home, but she wouldn't sit properly outside of the house despite all of us rectifying her whenever we could. Any suggestions on how to deal with this?

Another issue is that she dislikes talking to her classmates cause all of them speaks Mandarin, of which I don't know what to reply her with, since I have that same darn problem myself even as an adult.