Rape is often hard to prove because you can't prove lack of consent.

While this is false, it is one of Ethan's favorite claims because it provides a supposed justification for an AOC.

Potential rapists know this and it deters some rapes against minors.

Potential rapists already know rape is illegal. The burden of proof is relevant for the DA, not for the rapist. The rapist's consideration is whether they are going to get caught or not; and specifically regarding the selection of victim, the only specific way they can reduce the chance of being caught is killing her. Or maybe, short of killing her, enslaving her for life. Not by carding her before raping her.

Sexual encounters carry the possibility of emotional hurt at any age, but on average the chances of this and the severity go down markedly the older a person (especially a female) is.

Yes. That is called senility. It is even a defense in court for some things. And I intend to commit suicide if I ever reach that stage.