Cody is an absolute gun as far as I'm concerned. There is unequivocally nothing wrong with what he did from an objective standard of voluntaryism.

Even if Cody had knowledge that the girl was 16. What right does the government or anyone else have to tell a young woman that clearly
understands the repercussions of the act she's engaging in, that she can not voluntarily have sex with an older man?

It should be self-evident that what the majority within a country or society think about someone's ability to consent to sex has no basis on whether that individual can or cannot consent in objective reality.
Consent merely means having the cognitive capacity to understand what one is agreeing to and accepting these terms voluntarily.

The age of consent is obviously not set in stone so the question begs, what age is acceptable and can we arrive at an objective rational outside of the generalized ethics of a society?
In nearly every culture and society, 13-18 was considered adulthood and it was considered the norm for a younger woman to be married to an older man.

From a biological perspective, most children hit puberty between the ages of 9 - 15. Men are considered capable of procreating upon their first ejaculation which occurs 1-2 years after they hit puberty. If a woman is menstruating, they are ready to have sex and procreate.

An individual being at an appropriate level of self-autonomy or brain development is also not necessarily defined by age.
Many teenagers from the age of 13 display high IQ's well above the normal range of 'Adults' and are responsible for many ground-breaking discoveries e.g. 15 year old Jack Andrake responsible for inventing a pancreatic cancer detection tool and 13-year-old Terence Newton who invented a free energy device under $15.
Should people that are retarded in their mental capacity showing IQ’s lower than 70 be restricted from making decisions concerning themselves?

The current basis we have for Age of Consent laws around most countries are not grounded in objective ethics or science and often reflect values of the Elizabethan era where women needed to be protected from exploitation and marriage outside of wedlock. Although humans naturally have it within themselves to protect their young and those deemed as lacking wisdom, we do not have the right to prevent them from enacting their free will once they become free ages.
If one owns themselves and is capable of exercising dominion over their body and their mind, the harsh truth is one cannot restrict their capacity to make voluntarily decisions about what they do with themselves without violating their rights as sovereign beings.

Consent should not be based on the standard of the arbitary standard of age but on an individal assessments of cognitive ability or whether the said party has the capacity to emancipate themsleves from the Guardianship of their parent or carer.

Despite the often unwilingness of parents to relinquish guardianship of their children, once a male or female is able to excerise their agency and awarness to consent, you can not restrict their free-will
without violating their soverign rights.