Question:
Are there any US jurisdictions where, given two minors with some difference in their ages, it would be legal for them to start an "intimate relationship" the day before a particular birthday of the older minor but illegal to do so the day after? If so, how common is that situation? If not, how close do any get to that?
Context to help constraint what is a useful answer to me:
I'm jurisdiction shopping for a fictitious setting. Basically I want a villain to run afoul of that situation without having to lean too much on willful-suspension-of-disbelief with regards to legal matters.
That is despite the audience not being expected to be legal experts so I can (if necessary) lean on it some, for example by Frankensteining real laws from different jurisdictions.
Doing a little preliminary research, I noticed that the most commonly cited US age of consent in fiction is actually the most conservative one in the US rather than the most common one. As such, simply following other works of fiction isn't good enough for my case and I don't know of any non-fiction examples.