A suburban Detroit teenage girl has been sentenced to 10 to 20 years in prison in a 2014 plot to kill her family that left one of her siblings wounded.

The 17-year-old apologized to her family Monday before learning her punishment in Wayne County Circuit Court. She earlier pleaded guilty to assault with intent to murder.

Her adult boyfriend, Michael Rivera, is serving life in prison for attempted murder and conspiracy.

Prosecutors say the then-15-year-old girl stabbed her 12-year-old brother in the neck and tried to stab her younger sister in their Plymouth Township home. Police say that Rivera guided the girl from outside the house, advising her on which knife to use.

The Associated Press isn't naming the girl because Rivera was charged in a sex case involving her.