Surprised rank in school

One morning, the principal had a note to all the parents to get the card in school.

First, I saw the rank of my sister. She is rank 8 in the overall grade 2.

My card

Second, I saw the card of my brother. He is rank 6 in the overall grade 6.

Third, our teacher distributed the cards. My mom doesn't want to give me the card because she said it is a surprise if I have a rank. She saw I was rank 4, I was very happy because it is my first time to be included in the top 10 of our grade level.