Some states do not have a traditional statutory rape statute but instead look at the age differences, the actual age of the parties and other factors. In my stae there are forms of what might be called statutory that are misdemeanors. However do not expect any reduction if she is 15 and you are 21. You need to talk to a NC lawyer.
I agree with Mr. Kaman's general assessment of the types of potential statutory provisions. If you want a more definate assessment here on Avvo.com, you would have to provide more specific facts. Otherwise, follow his suggestion and discuss this with an experienced criminal defense lawyer admitted to practice law in NC. Good luck.
This response does not constitute legal advice. Given the nature of this website, it does not create an attorney-client relationship. This answer is provided solely for informational purposes, for you to use as a starting point when speaking directly with a lawyer in your State. I urge you to immediately contact an experienced criminal defense lawyer admitted to practice law in your State before you make any decisions about this case.