What to wear for a wedding barn dance?!

I'm having a major fashion dilemma - please help

I recently got married - we decided that a formal do wasn't for us, so we had a small family wedding abroad, and are going to have a barn dance next month to get to celebrate with everyone. It's going to be informal, and the dress code is casual. But I have no idea what to wear! As the bride, I feel I should wear something special (not a wedding dress, as we've already had the wedding, but something pretty) but on the other hand I'd feel stupid in something too dressy or glam when everyone else is dressed down. It has to be something that I can dance in, so nothing too short or too long!

Any ideas?

Thanks!
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