what2wear at Costume Awards?

Tonight is the night. First time Im going out since I gave birth to my son six weeks ago. But what to wear? Should I dress up or down? I hate to overdress, lats year I was wearing ripped jeans, high heals and a studded leatherjacket designed by myself... here are some options.. Sweaterdress from Acne styled with a leatherbelt, bag from Nina Jarebrinck, knitted tank from Samsø&Samsø styled with a sequined bra from Ebay, silverdress from Zara in combo with gold jewlerry and black booties from acne, nude vintage dress, London. What do you think?