I think these laws are fucked up. Look at that kid who went to prison for 18 years because he got a blow job from a 15 year old. They were both in fucking high school so they were EMOTIONAL EQUALS. There was nothing morally wrong with that scenario, because they're essentially peers. And what if he'd gotten the blow job when he was 17 just a few months earlier - that wouldn't have been wrong? It doesn't make sense.
Since the laws are clearly not perfect, you really do have to apply common sense to the situation. Grael and Flagg have a huge age gap - it's not like she's 19 and he's 16 - that would be a grey area IMHO, especially if they were both in high school or both in college.
Also, I don't think that Flagg's 18th (or 17th) birthday will make her NOT a pedo, since the relationship started when he was so young.