A teen charged with fatally shooting a friend at a South Florida high school has pleaded not guilty to a second-degree murder charge and carrying a firearm on school campus.

Teah Wimberly entered a written plea Thursday. She will be tried as an adult. If convicted, the 15-year-old could be sentenced to a maximum of life in prison.

Her next court date is Feb. 20.

Her lawyer has said Wimberly may need medication after a psychological evaluation found she had mental-health issues.

Authorities say Wimberly and 15-year-old Amanda Collette were longtime friends who had recently stopped speaking before Wimberly shot her at Dillard High School in November. She then ran to a nearby restaurant, called police and confessed.