How can I get her to actually knock, the both of them actually?

My mom and brother and sister are like that too. I get so pissed I just start yelling at them until they get pissed and leave the room. It's much easier for my brother and sister cause their 4 and 6 I just yell get out a couple of times and they leave, but my mom it's like never ending! My advice is do what I do. or just lock your door.