My gf got mad at an inappropriate joke

Guys I honestly don’t know who to go to or how to feel abt this because it’s a weird situation. I made a joke in an Instagram poll regarding what kind of food to a potluck we’ll bring and stupidly there was an option that said “my dih” and I chose that one, knowing my gf was in the same gc but I was expecting her to find it funny as well. It was already an option before I voted or even got added to the gc. Me and my gf ended up in a what was a playful argument about it at first in our dms but I could tell very quickly that she doesn’t want me to make a joke like that ever again and I could tell she was getting actually upset as we went on, so the mood is just weird now. I feel like it wasn’t a big deal since we’re not appropriate with each other either but idk how to go about this. I did seriously explain why I did it and apologized.