Bill
32053
The Tudor mini sub is a great choice that will last for years if not a generations.
It is not the watch for school but for all family events and special occasions it is perfect.
My other choice would be to look at the Seiko line of watches for a robust watch that will also last but at a reasonable cost. It is also not colorful and can work for a young lady. You just need to find the small size models.
Cazalea the Seiko Moderator I am sure can guide you. Send him a PM - Private message or just post the question in the Seiko forum as to which watch will fit a young lady.
Best
Bill