I see myself as a snail, always curled up and withdrawn inside her little cramped protective shell. This tiny snail, however, has always had beautiful dreams. Ever since she was a tottering baby, this little snail already wished that she would become a teacher. At three years old, she even pretended to be a teacher and used her grandparents, parents, oldest brother, and little baby sister still in her crib as students. ('the using possessive pronoun 'her' here is not clear because this sentence has more than one person. I would rewrite it as '...and littler sister whose still in crib as students')

Dethuong,
Pay attention!!!
Câu này perfect.....Coi chừng trâu lành làm thành trâu què đó.
Chữ đó là possessive adj.!!!