Aurora Police are offering a $5,000 reward for information that leads to an arrest.
Detectives say the shooting happened in the area of East 11th Avenue and Newark Street, which is across the street from Aurora Central High School, about 2:30 p.m.
Ten buildings, including eight schools, went into lockdown for about 30 minutes after the shooting.
Aurora Police say friends took the victim to the hospital, where 9NEWS learned she underwent surgery Monday night.
A neighbor who didn't want to be identified told 9NEWS some teens were standing and talking near the school. A couple of cars pulled up, one of them a black cruiser that eventually pulled a U-turn and headed towards a group of students.
"All those kids start flying away," the neighbor said. "Something was said, there was an argument and then we heard two pops. Pop, pop. I ran in the house and I told the wife, 'Get down, get down, get down.'"
Police say they are interviewing several witnesses at police headquarters. They are also looking for a black or grey primed Dodge Neon sedan. The car had several people inside, possibly four. Police say they only have a vague description of the man who was driving.
A spokeswoman for Aurora Public Schools says the high school will be open Tuesday. Counselors will be available for students and teachers.
Aurora Public Schools says all lockdowns were lifted about 30 minutes after they were issued.
Police say the buildings that were locked down were: Aurora Central High School, Jamaica Child Development Center, Kenton Elementary School, Lansing Elementary School, Peoria Elementary School, Vaughn Elementary School, South Middle School, Lyn Knoll Elementary School, ESC 4 (an administration building for Aurora Public Schools), and Hoffman Heights (an administration building where parents take students to register).
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