Left 4 Dead

According to her official description, Zoey is in her first year of college, which would make her at least 18 years old. Her outfit consists of a red jacket, white shirt, jeans and Converse shoes. She also keeps her hair up in a ponytail.
Zoey's design was originally based off of Alesia Glidewell, who is also the model for Portal's main character, Chell. Zoey's designs was later updated to resemble actress Sonja Kinski instead.

Official Description

After spending her first semester holed up in a dorm room watching old horror movies, Zoey was given a choice: Stop fooling around and get her grades up, or drop out. Now that the planet's overrun with murderous zombies, and all of her professors are dead, Zoey at least has the cold comfort that she's been studying up on the right subject after all.