My (33m) girlfriend (30f) invited her identical twin to a party, and I found myself feeling uncomfortable. Am I wrong for not wanting her to come?

I've been dating my girlfriend for eight months now. We live together and everything seems to be going great, except for one thing that has me a bit uncomfortable. <br><br>My girlfriend has an identical twin sister, and while I could tell their voices apart easily enough, I found myself having a hard time distinguishing between them at first. <br><br>Last week, my girlfriend asked me if it would be okay for her sister to attend a party with us. I hesitated for a moment, unsure of how to respond, and then I asked her why she would want to come. She said it was because she had never seen me in a party environment and she was curious.<br><br>I told my girlfriend that to be honest, I wasn't really comfortable with the idea of her sister being there. I explained that I had a hard time telling them apart at first, and I didn't want to accidentally call her sister my girlfriend's name or do anything embarrassing like that. She seemed to understand and said it was fine, but after that, she stopped initiating any talks about the party.<br><br>The party is this Saturday and my girlfriend hasn't mentioned it again. I feel like I've unintentionally made her feel bad or something.<br><br>Update: I asked my girlfriend what was wrong and if she was okay and she said that she's not and that she's also upset with me for not letting her sister come with us. I apologised and asked her again if I could meet her sister and she said she needs time and that maybe someday I'll meet her. <br><br>I told her that I'd go to any length to make her happy and make the relationship work.