Is it okay to overdress at my friend's 21st birthday? It's Mardi Gras Themed.?

I am confused on what to wear to my friend's mardi gras party. I am always known for the sparkly, flash. I am just that type of girl. I wanted to wear a sequin dress, and I discussed this with my friend. But now, she wants to wear a sequin dress. She has already told me what she wanted to wear. Do I not overdress, or what? It's mardi gras themed. So, I was thinking of a gold or green dress.