In what way is Adeline‘s life at Saint Joseph’s different than at home? (Chapter 4)

From the text:

My new school seemed so different from my old school in Shanghai. To begin with, there were fewer than a hundred pupils in this enormous place meant for a thousand. We were divided into six classes, depending not on age but on our ability to speak English. To my embarassment, they placed me in the beginners’ group. My classmates ranged from five to eight years old, while I was almost eleven. It was as if I’d never left kindergarten. Instead of algebra, I was doing addition and
subtraction.

We were not supposed to converse in Chinese with each other at any time. So I said nothing at all unless the sisters addressed me by name.