A person is guilty of rape in the first degree when he or she engages in sexual intercourse with another person:

1. By forcible compulsion; or

2. Who is incapable of consent by reason of being physically helpless; or

3. Who is less than eleven years old; or

4. Who is less than thirteen years old and the actor is eighteen years old or more.

Rape in the first degree is a class B felony.