Is AUTHOR wrong in the post ? POST : 
Alot of context is needed, myself and 16 others went on an exchange to Malaysia for a month through University. The girl in question, lets call her Sarah and the best way to describe her is 'stereotypical privileged white girl from Australia'. She wasn't that awful at first, but things started to go sour when I decided to go from Kuala Lumpur to Penang, the 16 of us had a group chat so often we'd put our plans in there incase others wanted to come. 

Turns out a fair few people wanted to go, as it was alot of peoples first time overseas I organized getting there and back and an Airbnb. We spent about 3 days there, however myself and two of my friends came down with food poisoning or something so they ended up spending time in the airbnb, skip to the last night in Penang the 7 of us that came went out to dinner as the two people who where sick ended up feeling better. Sarah started making snide comments about how stupid she thought it was to stay in an airbnb for the entire trip instead of exploring ect. Alice, one of the girls who was sick was quite upset at the comments.

So at this point myself and Alice are a bit wary of Sarah, even more so the next morning when we are leaving. Since I organized getting to Penang I had all the info for getting back. I made it super clear we should be ordering an uber by 8am that morning. Que next morning, Sarah and one of her friends decide that they would go get starbucks at 8:10 before heading to the bus station. This obviously annoys me and others as this was a university trip we did have a certain obligation not to leave anyone behind despite being all adults. I dont really say anything despite being annoyed and fortunately they made it just as we where boarding the bus.

At this point we are in week 2 of our trip, and the issues dont stop there. Those of us who noticed Sarah being rude just chalk it up to being in a stressful and new situation and try not to start an issues as we still have to deal with her for 2 weeks. I spend alot of time avoiding her, unfortunately she seems to pick on Alice quite a bit and this quite upsets her and me. I overhear Sarah gossiping about how 'I'm getting too involved' with organising things (like Penang), Sarah had been overseas multiple times as she quite often liked to bring up so she was a seasoned traveler. (She spent two weeks at Oxford University in the UK and managed to bring it up in every conversation, and according to her 'Melbourne has better coffee than Paris AND Italy'.

So que her birthday, all 16 of us are in Melacca with some people we met at Uni. It's her Birthday and she's made everyone aware and decided that we should all have dinner with her. Alice and I aren't thrilled about this, but since half of our group decided that they wouldn't we kind of felt bad. Initially I said I wasnt feeling well, so i went back to the hotel but when i heard that alot of people bailed i felt bad. Since the resturant they where at was close by I sent them a quick message saying order without me I'll be there in 10 minutes. I arrive and Sarah makes a scene about how I made them wait to order, and when I told her I actually I said order without me she still tried to attack me for it. Anyway the waiter makes a mistake with Alice's drink and Alice tries to explain it was wrong this confuses the waiter. Sarah makes snide comments about Alice ordering the wrong drink ect. Dinner is awkward but we make it through. That night we where planning to go out for drinks since our hotel had a really cool rooftop bar, but Sarah will be there. Alice and I decide to go anyway and just try and avoid her. We manage to find a nice secluded area, but unfortunately Sarah and one of her friends manage to find us and invite themselves into our conversation. 

So her comes calling out. Alice is completely done with Sarah, but she's definitely more sensitive and emotional the some people. Sarah then asks me if I would like to go to the markets with her and her friend tomorrow. She asked only me, specifying my name multiple times I front of 5 others. Alice takes I quite personally and decides to leave with tears in her eyes. Alice and I had become really good friends throughout the trip, and so when Sarah asked if she was feeling sick again I decided I would say something. Keep in mind I think I did I rather civilly. I told her that her actions had been coming off quite badly to myself and others. I didnt call her a bitch or anything I really wanted to. Anyway she starts crying and I apologize for saying these things on her birthday but we had all been suffering. I left and went to talk to Alice. She messages Alice to talk to her and instead of apologizing she said, and I quote 'well I think you took those things so personally because you haven't traveled as much or have as much life experience as me'. (She is 22, lives with her parents and works one shift a week. She told us they contributed most of her funds for this trip).

Anyway she never 'apologizes' to me and I didnt really mind. She avoided us for the rest of the trip.

Short story: Am I an asshole for calling out a girl for being consistently rude to myself and others for 4 weeks on her birthday after she made someone nearly cry.

Am I the asshole in this situation? I do kinda feel bad about doing it on her birthday but she really deserved it.