check the age of consent in your state. thats all that matters.
RAPE is a sexist crime, by saying that i mean: a girl cannot rape a guy, but a guy can rape a girl. Therefore if a guy dates and older girl, and they have sex, and she is older than the age of consent and he is younger, the worst that happens is she can be charged with certain sexual charges, not Rape. If a guy has sex with a younger girl, he can be charged with statutory rape.
Say your age of consent in your state is 17, and you are 18 and the girl is 16, and you have sex with you, she can file charges. However, depending on state laws, there are ways around this. For example, in New York, the age of consent is 17, but if a 17 year old and a 16 year old have sex, that is allowed. The law states no penalty for this, its almost like a loophole.
Why do I know this? I'm the son of an attorney. I've also been in this situation.