The Bar Code Tattoo, by Suzanne Weyn

Everyone gets the tattoo- so why doesn’t Kayla just go ahead and get it done?

From the book:

“Everyone has a file,” Amber said. “There’s been a file on everyone for years.”
“But people haven’t always worn their files,” Kayla argues.
Amber shrugged, unconcerned. “What’s the difference? Walk me to class.”
“I’m going home. School feels like a cage today. I can’t sit still.”