Can you prove that beyond any shadow of doubt that police are going to say “ok, this is a clear case of false accusations”? Because if you can’t prove it categorically, and things go bad, you’re in danger! The likelihood is slim that she would do this, but it’s there.

This is going to depend on your location and local laws. If you get into an argument or have a bad breakup with this now-adult, could she go to the police and say “the relationship started a month before my 18th birthday. He knew I was 17 therefore it was statutory rXpe”? If the answer to that question is going to warrant a police investigation, STAY AWAY FROM HER!

In the UK, this might be weird and skeevy to many, and you could lose friends & family for it, but it would not lead to a police investigation based on age alone. In some US states, I believe it would lead to some very serious consequences for you, the kind of which leads to jumpsuits and lists you don’t want to be on.

I don’t think you should even entertain anything more with her for so much as a second.