KIDS' bathroom - wall to wall mirror above bath and vanity?

I am considering getting a large mirror stretching above both the bath and vanity (wall to wall). The vanity will be 90cm high and the splashback would be 300mm, so the mirror would start at 1.2m above floor level and would go all the way to the ceiling (2.7m high ceilings). We are having square set (no cornices) in the bathrooms.

Do you think a large mirror stretching from one side of the bathroom to the other would be too much? Should we just have a mirror above the vanity instead? The vanity will be 1m long.

By the way, we are not having a shaving cabinet above the vanity as we figure with 3 bathrooms and 2 powder rooms there should (hopefully) be plenty of storage.

B