Is AUTHOR wrong in the post ? POST : Context: I'm twenty four and my sister is twenty and we live in our parents house. My sister has had parties in the past that have been mellow, and a couple that have made me extremely uncomfortable with how many people are there(my sister is aware of how uncomfortable these parties make me).
Recently, my sister told me she would be having people over on a weekend night while my parents were gone. This was fine but I ask for nobody to go upstairs or in the garage so they dont let out our animals. The night of I go about shutting and locking all the doors that need to be a locked and set up a gate up for the stairs. 
When I entered the kitchen I asked someone if the room smelled like gas to them. Someone had leaned against the oven and left the pilot on for who knows how long. I turn it off.
I look at the stairs and it seemed like somebody tracked dark wet mud all the way up to the top. I follow the trail and try to get into my parents room. My parents door was locked so I pick the lock open. I wasn sure what to expect when I walked into the room but it ended up being a guy in the bathroom. I knock on the door and tell him he shouldn't be up there.
 When i checked the garage someone moved everything and unlocked all the doors, again. I walk out to find four people sitting in my garage that doesnt have any lights sitting on the ground with the side doors open. They had let all of my moms indoor cats out.
Irritated now by the last few incidents. I find my sister who was in charge of the music. The music was very loud still so I yell multiple times for her to turn it down or off so I could make her look for my moms cats. I get her and a few people to go outside and help me find them. I was really upset during this time so and I told her it was really bad that someone had let them out and how upset I was. After a bit, fortunately we got them together and I put them all in my room for the rest of the night.
I walked out again and the room was filled with smoke and smelled like fire. The room was full of people yet nobody seemed to notice. Someone had leaned against the oven and turned it on causing a box someone set on it to catch on fire. I grab the flaming box and push through the group of people to set it in the sink.
The next day I get home from work to find my sister was loudly explaining to my parents on how upset she was that I yelled at her because the cats got out painting me as the villain of the night. Frustrated, I walked into the room and asked why she was saying such mean things. It turns out her best reason for saying all this was due strictly from the fact that I yelled at her about the cats. At this point with everything I had dealt with the night prior I exploded. I told my parents everything that had happened the night prior. She had nothing to defend her point, but now she wont talk to me and has disinvited me to our trip to various music festivals we had planned together this year. AITA for being so mad?