Last Friday night, Amy Steverson from Maryville, Tennessee got her hair done, did her makeup and put on the dress she had spent ages choosing.
But when she arrived at the school she was told her outfit was "too revealing" and reportedly "told by a teacher repeatedly" that "us big girls gotta cover up".
Her friend Bronte's mother Tiffani posted a pic of Amy to Facebook, explaining what had happened.
"Last Friday night was her senior prom. She spent time looking for the perfect dress, got her hair done and was meticulous in putting her make up on. It's an exciting time! She proudly had her pictures made, and why wouldn't she? She looks like a princess!
"Arriving at the prom, she was stopped at the door. She would not be allowed in because her dress was "too revealing". After spending some time in the restroom crying, she was told she could go in if she wore the vice principal's tux jacket, which mind you, did not cover her chest."
Amy did end up wearing the suit jacket so she could attend the prom but Tiffani believes the supervising adults failed her.
"This young girl was SHAMED for having breasts. Her excitement during this memorable time of her life turned into embarrassment at the hands of adults who are supposed to be leading her."