3 points ·
I'd imagine that "school" in that context is used more broadly and encompases stuff like kindergarten.
A look at their website shows that they seem to also have a preschool and elementary school. It even currently says that you can enroll your kids born 2023 now "even if they don't start in 2026", which implies that starting 3 seems to indeed be a reasonable time to join their preschool program.