Replying to Underage sex on a birthday - she turns 18 during the act

I was wondering, how would this fly in a court of law? If the age of consent is, let's say 18, you end up hooking up with someone on their birthday and begin the act while the person is 17 and finish when the person has turned 18.


I'm intrigued. Of course, not in support of sexual abuse of children through legal issues, but don't you think it is kind of funny in a way:

17 years and 364 days - DON'T EVEN THINK ABOUT IT!!!
1 extra day - Sure, go ahead.