AIO for being mad my gf refused to dance with me specifically in a party but danced with others?

We went to a family party. She said she wanted to dance. I said we could dance. She refused because she said I was a bad dancer, so it wouldn't be fun for her. Then she proceeded to dance with family members ranging from children to old people.

I felt really bad because I am her boyfriend, we're supposed to be partners and not abandon the other over skill issues. Also how am I going to learn dancing without practice?

She says I am overreacting. Am I?