My family thinks of me in adulterated ways

When I was younger I moved in with my dad, stepmother, and stepsiblings. We used to fight like cats and dogs it was horrid! But I was also young(about 7 or 8). My step siblings were older than me and knew more so they slowing but surely got me into their games and unfortunately..porn like videos. It was fine at first but then they started touching me inappropriately and even ruined my play time. I'd be playing dolls and my stepsister would start getting sexual about the scenarios and suggesting she knew something more "fun".

Now this was years ago. I figured she'd changed. We're all in college, going to college, or finished. But no, when I came to visit she insisted on less than appropriate engagement in her bed room, and when I refused the first few times she was desperate enough to suggest I just lay there, and she do all the work. It hurt becouse I wanted to be friends with her with a new matured mindset, and trust her but to no avail..

After that it got worst. I went to stay with my aunt and her adoptive daughter. It was fine at first but when my aunt left we went to the basement and like my stepsister and brother, she insisted on sleeping with me even with cameras in the house. I was disgusted to say the least and felt morbidly uncomfortable but now she's coming to visit for my graduation. I've never told anyone about this or the countless others who touched me in unsavory ways, but now that she's coming to my house and sleeping in my room, these memories and emotions are hitting me like a train. I wanna trust that she changed, but I'm scared it'll be the same thing all over again.

TLDR: my step siblings and adoptive cousin touched me in ways I didn't like, and now that my adoptive cousin is visiting I'm uncomfortable.