My daughter is acting weird. Please help?

This sounds like with my Middle sister and Dad, But this seems much more intimate. She seems like VERY close to you like more than Father and Daughter type situation. Maybe you should tell her that you are her Father and she is your Daughter. Just simply try to imply that you are family and maybe you can help her inside with friends, like maybe try to get her more out there, but on her own in a sense.