Destiny Coulson, 17, pleaded guilty in Berrien County Circuit Court Monday for second-degree murder.
As part of her plea agreement, her second count of felony firearm was dropped, and her prison time will not exceed 16 years.
Coulson was charged for shooting and killing her boyfriend, David Quinn Jr., after an argument at his Eau Claire home in January.
Coulson was originally tried in juvenille court, but moved to be tried as an adult in June.
Her sentencing will be on October 8th by Judge Gary Bruce.