Madrina

Hello, I`m going to be the madrina for my neices quincenera. I`m lost on what to wear. Could I wear whatever color I wan`t, should I stay short lengh or long? I have 3 dresses in mind one is long formal evening gown in navy blue, long beutiful rasberry color, and the third a long beutiful berry color. The dama will be wearing tea lengh dresses in royal purple. I`m not to crazy about purple, (I should look different than the damas, right?) Thank you!

Lourdes