I just wrote this up for a friend in an email, so I'll paste some of my favorite books in the parenting genre. Here are the highlights from my first pregnancy binge-reading:
Good parenting. Allowing children to make mistakes and suffer the consequences is part of their growth. Just follow up with a discussion, where you ask questions about what choices she made and what she needs to change. Also, may want to suggest she discuss her mistake with the teacher.
Book on point called How to Raise an Adult.