I have kids and I wouldn't want my teenaged son having sex in my house, that says " I am ok with this". At least she is putting it out there and telling you that she is not OK with it because no matter how old you think you are, you are still her kid and parents don't want to think about what is going on in the other room. She might know you are having sex but it is different when it is in your house.

Honestly, and i am going to get on my high horse for a minute and I may look bad for doing this but I have PTSD and I have a stressful professional job, a house and 2 kids and I can do it because I work my ass off at healing this shit that has been put upon me every god damn day! If you have a problem you have to deal with it head on or stick your head in the sand, if you stick your head in the sand then I can't feel sorry for you.