I (20) am the youngest of three children with two older sisters: Amy (25) who I've always been close with, and Suzie (27) who has always been mean to us and is known to play the victim. Amy had an unplaned pregnancy, Suzie had a lot of opinions on that and I'm the one who keeps to myself so she told me all about it. She said that Amy got pregnant by a random guy and she's such a bitch cause she, Suzie, was suppose to do that first since she's the oldest, and said a lot more. Amy needed to get an emergency C-section and since she never had surgery or been under anasthesia she wanted the whole family present. Only one visitor could be in the prep room aside from her bf. My father was already there since he works at the hospital and the rest of us arrived later. I went to see Amy after my mom,who was there for about 20 minutes, and I stayed for max 3 minutes before the nurse told me she needed to shave my sister for surgery, so I had to leave, and she would come get once done. Not much time passed before Suzie said she'd go in the room. I tried explaining her what the nurse told me, but she cut me off saying it's her sister, she doesn't care and Amy shouldn't mind, so she left. About 2 minutes later, Suzie storms in the waiting room, saying that the doctor was rude and told her WE had to leave. There was other pregnant women there, so we tried to calm her down and understand the situation, but she kept saying we had to go home cause that's what the doctor told her. My father went to see what happened and Suzie left. Amy's bf and my dad came back explaining what really happened. Basically Suzie kept asking the nurses at the desk to open the door so she can access the patients rooms, figured out how to open it on her own, BARGED into Amy's room, saying loudly "Don't worry I'm here, everything's fine" etc. After leaving, my mom kept calling and texting her to comeback and it was ok. Amy goes in the operation room with her bf, and my dad managed to be in the viewing room. Suzie came back and I ignored her. My mom, however, tried to talk to her saying we're here for Amy and its not about Suzie. She exploded about how it's never about her and its been that way since she was 15. It went quiet for a second (literally), when I saw my dad had texted in the family group that Amy gave birth to a healthy baby boy, and I hesitated before telling my mom and sister the news. My mom obviously was happy but Suzie rolled her eyes, sighed and said someting while looking pissed. I had enough, so I told her to just stop it. Suzie told me:

"Shut up. You have no idea what I went through. You're just a spoiled brat who always got what she wanted. You went through nothing"

I respond: " Me shut up? no you shut up, our sister just gave birth and we can't focus on that cause of you."

She just repeats how idk what she went through so I cut her off saying:

"Who cares, whomp whomp. Guess what, you're not the only one who went through something. Amy just got a c-section and all you can think about is yourself.

Atp she just tells me to shut the hell up over and over again. As I was getting up, I continue in a low voice:

"The only thing that matters rn is Amy and the baby, we can't even take a moment on that because of your little tantrum. You went through stuff when you were 15, get over it, you're 27 now acting like a 13 yr old. Grow up."

I left after that cause I knew I'd do or say something I'd regret. I went to a nearby bathroom cuz I was shaking so much, came back once Suzie was gone and my mom told me that she told her fuck you and left. I apolagized to my mom and she told me I shouldn't have said anything and let her be.

There's more to the story, but I've gone for long enough and I don't think it matters (could elaborate if needed). My family is coming over tn for Suzie's birthday and idk what to do and with what my mother told me, I feel conflicted. So AITAH for lashing out on my sister during our other sister's labour?

PS: English is not my first language, sorry for any mistakes and/or if it doesn't makes sense.