Pfeifer was driving a car that went off the paved road around 3:40 a.m. May 26, 2011, hit a concrete culvert and flipped. Her front-seat passenger, 15-year-old Journi Maas, was thrown out and fatally injured.
The plea agreement calls for Pfeifer to receive consecutive sentences. She faces up to 18 months for vehicular homicide and up to six months for DUI. District Judge Jared Johnson also ordered her to pay the $650 cost to summon potential jurors.