AITA for not wanting to wait an hour?

My girlfriend started taking classes again. She has been excited and wanted me to join her when I got back from a family vacation. She has lab which I cannot join but she states its only an hour long and I could wait outside. She said I could join her other class and then we get dinner. I get frustrated and have other things I would like to do since I have been out of the country. She got upset and I understand since I have been gone for a while but I feel like she doesn't need me to be there. I'm already spending the evening and night with her AITA