阅读下列短文，回答问题

My name is Cathy. I'm twelve years old. I study(学习)in a middle school. My father is a teacher. And my mother is a teacher, too. Sam is my younger(更年轻的) brother. He is only three years old. He is very cute(可爱的). I like him very much. Today we are all here. Because it is my brother's birthday. The man in black is my father. The woman in yellow is my mother. Where is Sam? Oh, he is over there sitting on a baby chair. We have a good time today.