How can I get my personal space?

I’m 16, so I obviously still live with my parents.

My biggest problem is that I can’t have my own space. They enter my room without knocking or letting me know they’re coming in. Or they come in and stand behind me and read over my shoulder while I’m on my computer. And it freaks me out when people stand over my shoulder. I get all nervous and stuff. I don’t know why. I’ve told them MANY times that I need my space. I’ve told them that my room is where I should be able to have my space. I should be able to feel comfortable. I shouldn’t feel like someone’s going to walk in at any moment. It’s so bad I’ve had to stop changing my clothes in my room because they might walk in. And usually, they just walk in and look around and touch stuff. And I HATE when ANYONE touches my stuff. They aren’t even in my room for any specific reason.

If I tell them to stay out they’re like, “Why? Are you hiding something? Are you doing something you shouldn’t be doing? If you weren’t then you wouldn’t have a problem with us being in there.” I’m a good kid. I have nothing to hide from them and I don’t do things I shouldn’t be doing. But that doesn’t mean I want them in my room all the time. And if I tell them to get out they stare at me like I’m over reacting about it and say, “Jeez.. I can’t even come in to talk to you.” No. They can’t. It bothers me. I hate when people invade my personal space. And my room is my personal space. Sometimes if I don’t lock the door, my mom will just walk into the bathroom while I’m in there. It’s getting REALLY old. And they ALWAYS gave my brother his space. They only went in his room if they needed to and knocked before they went in.

How can I get them to leave me alone? I can’t deal with this. I have no privacy at all. And don’t say “Talk to them.” because I’ve tried. It doesn’t work.

Sorry it’s so long. And sorry if I repeated myself a lot. I tend to do that.