Just a warning that there’s a lot of swearing because I’m absolutely livid rn.

So I’m 17 and I have a younger sister who is 15. So we have always had a terrible relationship. We could never get along but I blame my sister for it because she shuts down when something doesn’t go her way. I’ve given her money countless times cause she spent all of hers on weed and juul pods. She usually takes 6 months to pay me back and I always have to do something for her to give it to me. Rn she owes me 20$ and It’s been 3 months. She thinks she is entitled to everything and I’m so close to snapping I think I’m going to hurt her. She had become an entitled brat since she was 5 and my parents are still saying it’s “just a phase”. I asked her about the money she owes me today and she says in order for her to pay me back, I have to go out and get her a gram of weed. I lose my shit and just start cussing her out cause I’m done with her bullshit. She doesn’t have any more weed and is now almost crying because she can’t smoke and she’s begging me for some. I always fell for her stupid fucking guilt trip but this time I told her no. She said okay then I’m not paying u back and I sent her a text later saying “I’m done with ur shit and I’m not gonna listen to you anymore. You think your entitled to everything well your not. Don’t try to talk to me cause I’m just gonna tell you to shut up. I’m not giving you anymore rides, no more favors, nothing. Just fuck off and don’t talk to me.” She responded with “fine u won’t get any favors either” I asked her what she’s has done for me in the last 5 years and she came up with walking the dog for me like 5 months ago and that’s it. Ik she gonna come back begging for something but I’m just gonna tell her to fuck off. I’m still living with her because I have no where to go until I leave for college. But I plan to ignore her and when I leave just block her on everything. So am I the asshole for doing it at such a young age.