Is AUTHOR wrong in the post ? POST : So me and my gf have been dating for 3 months now. She doesnt like suprises and prefers to schedule when we spend time together, usually about 1-2 weeks ahead (we both work full time, including most weekends)

We met today, ate and watched some Netflix together but I couldnt stay for the night because I have to work tomorrow. We decided about a week ago, that i would come over the next day after my work, spend the night with her and then leave tomorrow in the late morning. This is where our fight started.

A well friend of mine, who recently moved to another city, decided to celebrate her upcoming birthday back home. She told me about her birthday plans about two weeks prior, which i totally forgot up until maybe three hours ago, when she reminded me and told me about where and when the party would take place. 

So heres my issue: I really want to attend that party, since there are also a lot of old friends coming back for the weekend who i‘ll be seeing for the first time in a couple of months. My gf however, does not get along with them all that well and also wasnt invited. She insisted i spend the evening, as originally planned, with her and not attend that party. I said No. Just like that, she got pretty mad and basically kicked me out.

So, AMITA for preferring a birthday over a night with my gf?

Also, apologies for any grammar/spelling mistakes, not a native speaker.