What makes school particularly difficult for Liesel? After Liesel’s 10th birthday, what is she enrolled in?

School was particualry difficult for Liesel because she couldn't read or write.

Although it was state-run, there was a heavy Catholic influence, and Liesel was Lutheran. Not the most auspicious start. Then they discovered she couldn’t read or write.

Liesel was later enrolled in the correct grade.

Nearly a month after school resumed, she was moved up to her rightful year level.