Moving schools is a big step, small things can make it a positive or negative experience. My daughter joined St Dunstan's in year 7 (seems a long time ago). She didn't know anyone else there and had come from an all girl's school. I remember giving her a pep talk about "it might feel like everyone knows each other / has their friendship groups" that sort of thing. It wasn't needed, everyone mixed in very quickly. I think quite a few join in the VIth form and the majority of newcomers are girls so she is very unlikely to be on her own. New students do also seem to get chosen for netball/prefects etc as well. Again, hope this helps.