A person may not engage in a continuing course of conduct which includes three or more acts that would constitute violations of § 3–303, § 3–304, or § 3–307 of this subtitle, or violations of § 3–305 or § 3–306 of this subtitle as the sections existed before October 1, 2017, over a period of 90 days or more, with a victim who is under the age of 14 years at any time during the course of conduct. A person who violates this section is guilty of a felony and on conviction is subject to imprisonment not exceeding 30 years. A sentence imposed under this section may be separate from and consecutive to or concurrent with a sentence under § 3–602 of this title. In determining whether the required number of acts occurred in violation of this section, the trier of fact: must determine only that the required number of acts occurred; and need not determine which acts constitute the required number of acts. A person may not be charged with a violation of § 3–303, § 3–304, or § 3–307 of this subtitle involving the same victim in the same proceeding as a violation of this section unless the other violation charged occurred outside the time period charged under this section. A person may not be charged with a violation of § 3–303, § 3–304, or § 3–307 of this subtitle involving the same victim unless the violation charged occurred outside the time period charged under this section. For purposes of prosecution under this section, violations of subsection (a) of this section that occur in separate periods of 90 days or more shall be considered separate violations.