For context, my friend wears hoodies and pajama pants EVERY DAY.
I reserved a table at a very fancy expensive restaurant for 7 people, her included. We made a group chat and the other ladies were showing the dresses they were going to wear, except for her. The dinner is in a few days. Yesterday, we were hanging out and I asked her about what she's wearing for my birthday dinner. She told me she was just going to wear something casual like she always does. I told her it was unacceptable and to please buy a nice dress for the special occasion. The restaurant is very high class but doesn't have an official dress code. I told her that she will not be able to go to my birthday dinner if she won't put in the effort to looking nice for my special day. She went off on me and left. Am I the ahole?
Edit: I have a photographer, I wanted to have an elegant party so I hired someone for photos. I went thrifting with my friend and offered to have her borrow a dress from me. She says she doesn't want to wear a dress and she can go with her normal outfits. This restaurant is very high class and have an unspoken dress code. Sure, they won't kick you out, but it doesn't look good for you. I don't know what to do, I want my friend to be there with me but she refuses to make the effort for one dinner.