Advice needed, my sister won’t leave me alone after she came home from boarding school.

So, I (17M) have a sister (18F) who just came home from boarding school for the Easter holidays. She was sent there at 14 (I think?) because she was a huge rebel and stuff. I refused to let her come home for my birthday celebrations (she can come home for her bday, holidays, and family bdays) for this reason:

My sister loves seducing the people I date. Male or female. My boyfriend (17M) is a very attractive, nice, handsome, sweet dude and I love him with all my heart. A couple Christmas‘s ago, my sister peeped at him while he was pissing and then tried to touch his chest multiple times after.

He’s obviously very uncomfortable around her, but he doesn’t want to confront her about it/doesn’t want me to confront her (prob because he knows I’d probably lose my temper and punch her). She came home for Easter a few days ago, and one of the first things I asked her to do was not come into my room when my boyfriend is over. Her room is literally at the start of the hallway and mine is at the end, so she has no reason to even go near my room.

When my boyfriend isn’t over, she has barely come into my room. She legit only come in one time (she’s been back three days) during the time he wasn’t there, and it was to borrow a hoodie because she needed to run to the convenience store down the street and it was cold.

My boyfriend has been over for a total of around 8 hours out of the three days since my sister has been back (this does not include the time he and I were sleeping while he slept over one night, then it would be around 17 hours). In those 8 hours, my sister has come in 6 times. After I specifically asked her not to. She never really had a reason to either, just to “say hi” or some bullshit. She even went into my room while I was in the bathroom and my boyfriend was sitting on my bed. She didn’t try anything (at least my boyfriend said so, but I don’t trust my sister as far as I can throw her. Which is quite far, she weighs very little).

Extra context: I live with my parents, my boyfriend lives with his. We’re saving up to buy a place. We’re in the US. My sister sleeps around a lot and quite literally lost her virginity at 13, on purpose. She has even tried to make moves on ME before (gross).

Does anyone have advice? My boyfriend says it’s fine and that he can handle being a little bit uncomfy, but I really don’t trust my sister. Am I just paranoid?