A Mississippi teenager will miss her high school graduation on Saturday after a federal judge ruled that the school district could prohibit her from wearing clothes that align with her gender identity at the event.

The 17-year-old, who is a transgender girl, and her family filed a lawsuit this week against the Harrison County School District after school officials told her she couldn’t participate in the graduation if she wore a dress and high heels, citing school policy that says boys must wear a dress shirt and pants and dress shoes and a tie, according to the lawsuit. Girls are required to wear a white dress and dress shoes, and the suit says the teen purchased an outfit within the dress code for girls.

School officials told the girl, identified as L.B. in the lawsuit, that she must wear clothes according to her sex assigned at birth to her graduation from Harrison Central High School in the coastal city of Gulfport of about 72,000 residents.

In other words, the lawsuit said, she “must dress in accordance with the stereotypical male standards, even though she entered high school as a girl and has lived every aspect of her high school career as a girl.” The suit said the teen has worn dresses and other traditionally feminine clothes throughout high school with no issue, including at her prom where she wore a formal dress and heels.

Policy forced girl to ‘decide between being herself, celebrating this milestone’

“The school’s discriminatory policy and court’s decision forced our client to decide between being herself and celebrating this important life milestone,” Joshua Tom, legal director of the ACLU of Mississippi, told USA TODAY in a statement.

Tom said the girl will not attend the ceremony. Graduation is scheduled for 6:30 p.m. on Saturday, according to the school district’s website.