"Despite Mutual Agreement."
Mind you, I am not making a judgment call here. I am only stating the obvious. Rules are not inherently evil, and many thrive by actually having them. Nevertheless, norms often predict shame and distress in spite of sincere original voluntary engagement.
Key points being:
Certain acts, though engaged-in willingly and voluntarily, often lead to later shame and hence, later psychological challenges.
The assertion that age alone determines ability to consent, is a rather static and "lazily un-researched" standard. Truly, though. Individuals do not matter in their personal maturity and individuality to the law. This is not a sly go-around. It is today's reality.
If my approach to this bugs any of you, just blame Young Sheldon.