Continuity mistake: When Mia and her friend are riding their go-peds at the beginning of the movie, they leave with jackets, they go up the hill with no jackets on, then, when they arrive at school, their jackets are on again.
Suggested correction: The shot where they go up the hill without jackets is a different day because Lily and Mia are talking about Mia's father being dead and Mia meeting her grandmother.