DD1 was in composite last year and I really worried she would fall behind (was a P/1) class, but it was the complete opposite. She thrived, had to make new friends as her P friends were in different rooms etc. This year she's in a 2/3 class and I couldn't be happier. Hate the teacher with a passion, but I've been told she's strict but good too.

If you're not happy, give it a few weeks then speak to the school, it's early days and things could be better then you think right now. I would bring up the bully concern now, however!