Forty-three-year-old Kathleen Holey plead guilty to one felony count of assisting in the suicide of her son and the attempted suicide of her daughter-in-law.
The agreement will allow her to avoid a trial, which was scheduled to begin next month.
Holey admitted she knew her son and his wife were planning to kill themselves and provided them with prescription medications. She also admits to driving them to a remote Clinton County location and leaving the two teens to die.
Kathleen Holey faces up to two-and-a-half years in prison and a $5,000 fine; she will be sentenced on Oct. 14.
Kathleen Holey's daughter-in-law is now serving a four- to 15-year sentence for her role in her husband's alleged rape of a minor.
The Associated Press Contributed to this article