A child of my neighbor goes to school there. She said it was good, and the children's grades were progressing steadily. At night, I can always meet children who come back from self-study, and the teachers there can help them do their homework in addition to attending classes. Your sister may not have adapted to the teaching in Nanjing, so hurry up, or you will lose too much knowledge and have to make up. I hope I can help you.