I need to get a dress for my cousins wedding help!?

my cousins wedding is coming up this month i need a dress to wear to it but not sure what kind i should wear, its a Italian wedding and they have Loads of money i want to fit in but i don't want to look to flashy i have short hair dark hair but i also have clip in extensions i could put in. i have a roundish face and i`m really short im also 16 skinny + not much of a chest. post some pictures pleasee! <3