The thing about the teachers age and appearance that the translater didn't understand.
She's saying that, even though the teacher's an adult, she's acts no better than a child. Even her students act more like adults, even more so than the teacher herself. She resents her for this and can't stand the childish and cowardly way she lies about everything. Even going so far as to continue the charade in such a serious situation.
The thing about the teachers age and appearance that the translater didn't understand.
She's saying that, even though the teacher's an adult, she's acts no better than a child. Even her students act more like adults, even more so than the teacher herself. She resents her for this and can't stand the childish and cowardly way she lies about everything. Even going so far as to continue the charade in such a serious situation.
I hope this clears things up!