I don't have any privacy at home?

Hello. I am a 16 year old girl who is currently living in a bedroom with 2 other people. I would be okay with it if it was with young siblings, however I am sharing this room with two grown adults. Everyone needs privacy, even teenagers, and although it is hard for me not to sound entitled in this post, I also need privacy. My mother sleeps in the same bed with me (it's a queen sized bed so it's not really weird) because she snores loud so my dad can't sleep in the same room as her. My older sister who is almost 25 works in a call center and was told she could work at home, and is using my room for her work (which means my desk is completely taken up by her two monitors and all her stuff). I understand why this situation is happening, but my sister works until 6:30 pm, which means I'm not allowed in my room until she leaves. This leaves me feeling suffocated by them, and when I try to set boundaries (like no drinking in my room, no touching my things around her, not leaving trash or dishes) I am disregarded and laughed at. I don't know what to do, and I just wanna be able to have my stuff to myself and my boundaries respected, even if I am 16. Is there anything I can do to fix this problem? Thank you.