CASTLE ROCK, Colo. — A 17-year-old Colorado girl who pleaded guilty to plotting to shoot students and teachers at her school has been sentenced to five years in juvenile detention.

Sienna Johnson was sentenced Friday after earlier pleading guilty to a juvenile count of conspiracy to commit murder and an adult count of felony menacing. She was sentenced to four years on probation for the menacing charge.

In court on Friday, Johnson told the judge she’s not the same person she was when she and her co-defendant concocted the Columbine-style shooting plot at Mountain Vista High School in Highlands Ranch.

When Johnson turns 21, a judge will have the option of placing her on probation or sending her to an adult prison to serve the rest of the five-year term.