FYI there is no state where the age of majority is lower than 18.
the age of majority is 18 in MI but there is a problem with the juvenile court having, or not having, jurisdiction over a 17 yo.
here are the rules on jurisdiction of the juvenile courts:
http://www.legislature.mi.gov/(S(hag1kl55zx3og2f5pi3ugzej))/mileg.aspx?page=GetObject&objectname=mcl-712a-2
We also have this little bit in the law as well:
http://www.legislature.mi.gov/(S(xb3rkl5511ogxmr2szg4sf55))/mileg.aspx?page=GetObject&objectname=mcl-712a-1
(h) "Juvenile" means a person who is less than 17 years of age who is the subject of a delinquency petition.