I think a couple of days ago one of the DUmmies opined that a person had reached adulthood at 31.
I read that a persons maturity ceases when they start doing drugs or heavy amounts of alcohol. If they are 16 when they become substance abusers, and continue for 30 years, at the age of 46 they have the maturity of a 16 year old.
DUmmies have two strikes against them without substance abuse.