根据短文内容，判断下列句子的正误。

My name is Ling Feng. I am a Chinese boy. At school I have a good friend, Mike. He is an English boy. He is twelve, but I am thirteen. We are in No. 5 Middle School. We are in the same grade, but we are in different (不同的) classes. Mike's sister is not a student. She is four. His mother can look after her at home.