The Butterfly Club - Jacqueline Wilson - Bog

Luckily, they look after teeny-tiny Tina wherever they go - but when the girls start in scary, super-strict Miss Lovejoy's class, they're split up, and Tina has to fend for herself for the first time. Tina is horrified when she's paired up with angry bully Selma, who nobody wants to be friends with.