AITA for telling my sister she can't bring her kids to my small apartment, and telling her to grow up?

I (26f) have a pretty small apartment, but it's perfectly fine for one person. It's two bedroom, but I'm in one and my best friend lives in the other. She only comes over a few times a week, and only if I ask her to, because she has two little kids of her own and her place is a total mess for kids.<br><br>My sister (32f) and her two kids (4f, and 7m) live across the hall. We've been in the building since I was about 18, and I've always had a great relationship with my sister. When I got my apartment, I subletted it for a year while I traveled. When I came back, she begged me to let her stay with me for a few weeks, and then I began to look for another place to rent. I broke up with my ex about a month after I moved back.<br><br>She moved in with me and stayed for about a month and a half, then found her own place. It's another two bedroom apartment across the hall, but since the place is a total dump. She says she's going to move soon, but I'm not sure I believe her. She has let them come over a few times, but never for more than a few hours.<br><br>She just called me to let me know that she's working a 12 hour shift and won't be home until evening, and that she's bringing her kids over for the day and they'll watch TV all day. I told her no. I told her she's an adult, and that I'm an adult and I need a day off too. I pointed out that she's trying to live in my apartment for the day, and then act like her place is good enough when she's not used to it. She got mad at me and said I was being an AH.