Since Washington State Juvenile Disposition Guidelines have stated the age range a juvenile could be tried in juvenile court of jurisdiction, it would be easier for the judge to determine if the person should be sentenced in juvenile or adult court jurisdiction. The confusion of the exact age a person is fully mature and should be consider adult makes it hard for judges under blended sentence to determine the appropriate court of jurisdiction for the juvenile. Following a research in psychology and neurology that confirms that young people’s brains are not fully formed until in their mid-20s, some people presumed that juvenile under 21 should not be tried as an adult. Contradictory to what the research have claimed, Catherine Rampwell in her
