Study As A Boy

I had a junior in my high school. She had studied in boys schools up until standard 8. It was a village school and she was a shy kid. Due to some family issues that I don’t know properly, she studied there posing as a boy. As she talked too little and was one of the attentive students in the class, not many were her friend. Also, she had a slender body and she was a late boomer as well. So, feminine features were not visible during her study as a boy. However, when she changed to my high school, she decided to get in as a girl. I heard that she used to avoid answering which school she came from.
However, high school was very tough for her as she was the only late boomer in the class. Though she started her period around the end of standard 8, she was not developing boobs properly. By the end of standard 10, she was stuck with an A cup, whereas her classmates were having B and C mostly. She used to be shamed a lot for it by the girls. I heard she was being told iron board, FBL (Front Back Level), runway etc. I felt very bad and I tried talking to her but she was hard to talk to. Even in the washroom girls would pinch her small boobs. I stopped a few instances though. She did not grow even at the end of standard 11 when I left high school. I met her again at my University but this time she had a bf and was happier than before. I heard that boy was her classmate in the boys' school.