AITA for finding out the truth?

I (f17) and my sister “addie” (21f) have always had a rocky relationship growing up.

this past week my aunt and grandma flew out to visit. Addie was still taking finals so she only had 2 days with them and i got 6 days. the days she wasnt there were really fun. on Sunday we went to a state park to hike and Addie had told me that my aunt was bored because of us. it made me rethink my entire few days that i had spent with her and i decided to just let it go and have the two of them catch up. on Monday my aunt surprised me with a graduation party since i graduated early. everyone decided to get dressed so we could take pictures, eat and then play a game. i was ab done w my makeup when addie came in my room. she said her and my aunt were going to the pool. i said “if i didnt just put on all this makeup i would go”. and she insulted my makeup saying “you cant even tell the difference” and “your actually ridiculous for taking so long” she then proceeded to say that our aunt is bored and she hasnt been doing anything and that i shouldn’t had put on makeup. even though nobody told me plans about the pool. my aunt left today but my grandma is still here. Addie came in my room and asked if i wanted to go to walmart w them. i said no as i had just got home from running errands all day. she then said “ik your not gonna spend time w her just like auntie and shes gonna be so bored” i finally texted my aunt and asked if she felt that way. she instantly denied it and said she wished she had more time w me but wasnt bored at all.

Addie came in my room to ask to go to walmart again saying its my “last chance” i told her “no im gonna take a bath and relax” she then called me a “lazy fuck” and “it’s literally a quick drive” i said “its 20 mins away and ik you want me to drive because you dont want to get gas” she said i had no right to assume that and “if only auntie could see this now” i then called her out saying “i talked to her about how you told me 3 different times she was bored of me and she said she never thought that once. and even if she said it, its not your place to tell me and make me rethink this entire situation and make me question what i remember. its so unnecessary. i was so happy until you came w us and started spitting negative shit out your mouth. narcissistic asf. like seriously tho whats your fucking issue” she tried to say something but i interrupted her and told her to get out. shes now at walmart with our grandma and is saying that im the asshole and she did nothing wrong, so wibta?