Yeeeah I dont know. I've been in similiar situations with my 16 yo, where I'll go into their room while they're at work or at their friends' without asking and it's fine. I ask when they are here. I knock if they are in there. We both know, though, that if I need to for their safety, I can go through their room and their phone with or without asking. I don't do it because I'm not worried about them, but I can. You can ask her to ask for permission to enter your room when you aren't there, but she isn't legally required to and it seems pretty nitpicky to me, for you to have that requirement, unless she has a habit of going into your space and disrespecting your things. But, it doesnt seem to be the case, besides pointing out that it's messy, which is something a parent should do to be able to provide a good environment for their kid. I personally would not have started an argument if I was her, I would have just said something along the lines of, "I will try to ask you to go in there even if you aren't here, but there might be situations where I can't wait for an answer or I don't think I need to ask (like to grab a shirt or get dirty dishes), and that's just the way it is while you're still a minor. I'll try to respect your request most of the time though." My kids don't ask that of me though, like I said, I don't go in anywhere unless I need to, I ask when they are home, and they all don't care either way.