What to wear to a 1920 's themed party?

Hi I've been invited to a 1920's themed party by my mums friend. Im 13 and there will be mostly adults there. I'm really not sure what to wear, i don't want to look tarty or anything. I thought maybe i could do like oldschool glamour, please give me some ideas. (btw this party is tommorow so theres minimal time)