Section 22.011 of the Texas Penal Code makes it a second degree felony (2 to 20 years + a possible $10,000 fine) to have virtually any kind of sexual contact with a person legally defined as a child ("a person younger than 17 years of age." TPC Sec. 22.011(c)(1). It is an affirmative defense that "the actor was not more than three years older than the victim" and was not a sex offender at the time of the offense, but having an "affirmative defense" means that you are allowed to present that information at a trial, and you do not want to be in a position of having to do that. Tread carefully. Neither the girl nor her parents can give you "permission" to violate the law, so if someone gets angry with you two or three years from now, you could be in a heap of trouble.
This answer is intended to be taken as general information and not as specific legal advice. You should always consult a qualified attorney and make him familiar with all the relevant facts in order to get proper legal advice. Every case is different, and they must be evaluated on a case-by-case basis. David N. Smith 812 W. 11th Street, Suite 201 Austin TX 78701 (512) 457-0100 defenseattorneysmith.com