(a) Notwithstanding the provisions of section one-a, article eleven-a, section four, article eleven-b and section two, article twelve of chapter sixty-two of this code, a person shall not be eligible for probation, home incarceration or an alternative sentence provided under this code if they are convicted of an offense under section three, four, five, seven, eight or nine, article eight-b, chapter sixty-one of this code, are eighteen years of age or older, the victim is younger than twelve years of age and the finder of fact determines that one of the following aggravating circumstances exists:
(1) The person employed forcible compulsion in commission of the offense;