If she's not ready to be toilet trained, then can't force her.
I will bring her to choose her sch bag, let her get excited about sch & hopefully adjust easily.
If you can, just bring her round to the sch a few times so that it won't be so frightening when she starts sch. Better still if the teacher allows you to bring her inside. Introduce your child to her teacher before hand, it helps too.
All the best!