Replying to Incest or no?

So here's the situation. A few weeks ago, I go home with a girl at a party and we have a good night together. Not long later, I see her posting on our school's ridesharing forum to go see her family that live in a town on the way to see my family, so since I'm a standup guy I offer to drive her. It's a fine trip, but when we show up at her place and I'm talking to her mom, I realize she has the same last name as me. I commented on it and her mom says her parents moved up from the exact same area of the states my grandparents are from. Since I use newschoolers to make all my most important decisions, do I keep hooking up with her? She is solid 7 and willing to forget about this if I am.