Is my friend being rude by not wanting to come to my dinner?

[claptrapwrap]

So I have recently moved to a new city. My friend is nagging to come and visit. I am very busy, so this was the only weekend I could do for the next months. First of all she wasn't sure if she could, but then when told it's this weekend or not at all unfortunately then she was free.

This Friday I have a fancy dinner that I have a +1 for, free. It is formal, so I mentioned to friend that is what we're doing for dinner. No, she doesn't own any formal clothes suitable. So I said, not to worry, save on packing space and borrow what you like of mine. She thinks she will look silly, even though we're the same size.

I then tell her the menu, she refuses to eat vegetarian food. The main is something that "makes her want to vomit" and she "abhors it".

Leaving me unsure what to do, going elsewhere for dinner will then cost me money as she can't be bothered.

Am I being unreasonable to want her to come with me?

You don't sound very nice

Why are people not understanding this?

Because it's not been presented in a logical order. In the first post OP says her friend is coming this weekend as it's the weekend OP is free, only she actually isn't and has told the friend they're going to a formal dinner. Friend, according to that post, seems to immediately object. Subsequent post then says that the friend agreed to go to said dinner. And, let's face it, OP isn't actually coming across as even mildly liking this friend, which makes it all the more muddy.

then tell her the menu, she refuses to eat vegetarian food.

How bizarre. Does she eat meat with a side of meat for every meal, then?