Gypsy Rose and Amelia Bird Similar Stories Different Sentencing Why?

Amelia Bird's ex boyfriend Chad Brantley murdered her mother and shot her father injuring him badly. Amelia was put in prison for life because Chad said that she talked him into doing it.

Gypsy Rose Blanchard's boyfriend Nicholas Godejohn was manipulated by Gypsy to murder her mother. Gypsy admitted she talked Nicholas into it. Gypsy only served time for 8 and a half years. Nicholas has life in prison.

How does this make sense? Amelia was a minor when the crime happened for her. Gypsy Rose was 23 when her mother was killed by her request. They were both put in prison in MIssouri.

Make it make sense?