Now that your girlfriend's parents know about your physical relationship with her, it is important for them to know that you are both acting in a responsible way. This means practising safe sex (i.e., using a condom) to prevent pregnancy and the transmission of sexual diseases. It will be primarily up to your girlfriend to deal with her parents.

      You don't state your age which might play a big factor in just how accepting your girlfriend's parents will be. Be calm, don't do anything to fuel the situation. Be supportive of your girlfriend (she's the one who has to live with her parents!) and see what happens after the initial shock wears off for her parents.

      Please visit the following websites for additional information now that you are both sexually active.
      BIRTH CONTROL CHOICES FOR TEENS
      TEEN PREGNANCY