Legal Question in Civil Rights Law in Missouri

Yes. If you keep her away form her parent's home without their permission, you might be subject to kidnapping charges. It isn't legal for you two to engage in sexual acts. Do you want to have to register as an offender for the rest of your life? If you're okay with that, and possibly doing prison time, then do what you feel. Otherwise, use extreme caution is having a much younger girlfriend. Also, know that a sixteen year old girl can view the world and other people much differently than she did at fifteen. Her recollection and memory of what was consensual or not, can change dramatically.

Good luck