Read it. I provided the link for good reason. The words “male” and “female” do not appear in the relevant MS State law.
As to your first example, a 15 year old girl who has intercourse with a 13 year old boy may well commit statutory rape, and should face the appropriate penalty. See (1)(b)(ii), specifying a 24 month age difference when the child is under 14.
As to your second point, if the boy is less than 24 months older than the 12 year old girl, then he did NOT commit statutory rape. If 24 months (or more) older, then he did commit statutory rape.
So “yes”, age matters.
Sex of the older person does NOT matter.
Read the law. It’s clearly written.
My point was that in THIS situation, whether it’s statutory rape depends on the age of the boy.