Bullying on breast size

So at my high school we have a lot of judgemental people. Awhile back i got changed for PE and this girl walks past me and my friend and she says that we are lucky we have small boobs. She kept laughing about it and always bringing it up during growth and development lessons in front of the whole class. I now feel like I’m not like the other girls in my school and I feel so uncomfortable with my body more now😓 any advice??