Am I being selfish because I refuse to Dance?

So my friend is getting married and asked me to be one of her bridesmaids I was happy she asked me and of course said I will do it. Now she is saying she wants to do a coriographed dance with her and all the bridesmaids. So the thing is I don’t dance even my husband that I’ve been with for 10 years has never seen me dance (except slow dancing together). So I told her sorry it’s a really cute idea but I don’t want to be apart of the dance. This made her angry so I told her if she doesn’t want me to be a bridesmaid because I don’t want to be apart of the dance then that’s fine (even though I already spent over $200 on the dress and shoes).

So basically she is saying I’m being selfish when it’s her day by refusing to dance. I have really bad anxiety and this makes me very shy and embarrassed to do things like dancing so I just won’t do this.

What’s your opinion am I the one being selfish here?