Fucking my slutty granddaughter Sadie Pop

My step-son married this lady that has sexy dirty little 18 year old step-daughter. I've spent a lot of time with her, taken her college clothes shopping, out to dinner and even bought her a car when she graduated. They think it's because I like being a grandpa, but really it's that I have thought she was sexy and adorable way before I should have. I've always thought she could kind of tell and the other day she proved me right.