If the court obtains jurisdiction over a child under this subtitle, that jurisdiction continues until that person reaches 21 years of age unless terminated sooner. This section does not affect the jurisdiction of other courts over a person who commits an offense after the person reaches the age of 18. Unless otherwise ordered by the court, the court’s jurisdiction is terminated over a person who has reached 18 years of age when he is convicted of a crime, including manslaughter by automobile, unauthorized use or occupancy of a motor vehicle, any violation of Title 2, Subtitle 5 or § 3-211 of the Criminal Law Article, or § 21-902 of the Transportation Article, but excluding a conviction for a violation of any other traffic law or ordinance or any provision of the State Boat Act, or the fish and wildlife laws of the State. A person subject to the jurisdiction of the court may not be prosecuted for a criminal offense committed before he reached 18 years of age unless jurisdiction has been waived. The court has exclusive original jurisdiction, but only for the purpose of waiving it, over a person 21 years of age or older who is alleged to have committed a delinquent act while a child.