Search Results: how to get a second date

I discussed with a friend about going to Germany in September since February ( no real plan: an exact date or sth, just that we'll go), a couple a days ago we also decided to go in a citybreak. Somehow talking about the second trip made first also more important and we decided about a date. She told me she wants to ask some more people and I said ok, except X week. Next day she tells me that they want to go in exactly that week. I say.. Ok.. This is Wednesday, Thursday she tells me we'll bring 2 more people with us in the citybreak. Like.. I am driving, we were the ones that created the plan together and without any question the 3 people team became 5. What makes me more angry is that i I wouldn't have asked sth that day about the citybreak probably I would have found out only when they were entering my car.

I got a bit angry, I found an excuse and told her we'll go nowhere.

What do you think? Is it ok what she did or not?