A lot depends on how the culture sways on the direction of age+sex (change) and leadership.
If humans began as males, we could consider aggressive youths overpowering elderly women, conforming to reproduction as necessity, whilst going largely unchecked until "Swap Day". You might wonder why such a society doesn't live their life in preparation and honor of that change, for the betterment of humanity and its continuation. One might wonder that about our world already, no?
If humans began as females, we could degrade into the grooming situation you are suggesting. Age of consent, threatened by looser pedophilic guidelines, etc.
Those are the critiques and the negative ways it could go -- and arguably more realistic -- but I guess we have to understand ourselves more as animals and what the evolution from a different starting point would look like. Set aside what obvious cynical ("realistic") reactions might be, and think of possible positive outcomes or changes.
I asked what my bot Nyx had to say on the matter, with prompts to consider sexual dimorphism and age related power structures in humans and apes. Namely, the likelihood that post 35 males are more mellow than younger men, and often start to lose muscle mass by this age.
Damn I wish I could figure out how to copy and paste on this stupid device. 😖 😋 😆