I agree with the comments that generally relate to treating her as a roommate and establishing expectations regarding how you do things in your house (i.e. taking care of dishes after eating, doing her own laundry). Since she is living in your house I think some expectations regarding home maintenance are appropriate (i.e. how often she will clean the bathroom she uses so as to prevent mold/mildew buildup). I am also of the belief of your house, your rules regarding overnight guests.

Some posters suggested she will be using your car but I didn't see that in the OP. If so, I think reasonable rules regarding use of the vehicle are appropriate but probably better if she has her own car.

Anonymous wrote:She will remain a child emotionally for the rest of her life.

As opposed to you, who sounds quite mature. Not.