Is AUTHOR wrong in the post ? POST : Only have a short time to post this for now, but will respond to questions later. Throwaway because any one of my friends will immediately know who I am based on this post.  

My group of friends has one girl who is (imo) pretty disrespectful. Late to everything and doesn't care about other people's time. Claims she's always broke but her parents pay for pretty much everything, and it doesn't stop her from going on vacations, going out to the bars all the time, doing a lot of fun activities. 

To give you an example we were all going camping last year, 7 or 8 of us. Most of us have to leave work or school early to get to our meeting spot. She's the only one who didn't have to work that day, and somehow she shows up an hour late. Doesn't apologize, acts like she wants to brush it off. It pissed me off and I blew up on her, but my friends seemed to think I was overreacting.  

Recently we had a pot luck game night. She shows up late, empty handed, because "She already ate". Well, I'm not sure how that precludes you from the responsibility of bringing something for the rest of us since you agreed to the pot luck, but okay. Anyway, within a few minutes, she starts loading up her plate. Initially I don't say anything, but as I'm getting progressively more drunk and see her eating more of our food, it just pisses me off. My wife and I went to 3 different stores (literally!) to get specific ingredients for the dessert we thought everyone would like, and specific drinks we knew people would like. She has the audacity to show up late, only think about herself, and then eat our food. I blew up. I called her out in front of everybody for being disrespectful and immature. I didn't call her any *insults* or swear at her or say anything that was purely malicious. I just told her, without sugar-coating, and in front of everyone, exactly what I thought.  

My friends brushed it off as "she's always been that way, she's not going to change, just drop it, who cares, we don't let her have any input in our plans" etc. I would have thought they'd be on the same page as me; it blows my mind that this late-20s girl isn't expected to be responsible.  She always has an excuse and doesn't think there's a problem. 

Anyway, AITA? My friends think I need to apologize to her so we can all get together again comfortably. I can apologize but I'm worried nothing will change and I'm not okay with that. 