Where can I buy petite dresses? (I’m 5 feet tall)

I’m F22 and I have a college formal coming up. I don’t have time to see a seamstress. I’m looking for a fun, midi/maxi, party dress. I’ve checked places like macy’s and I found the style to be too mature and want to keep it feeling young. I like some dresses at Abercrombie and ASOS but the ones I like aren’t available in my size. If anyone has any good stores or sites, please let me know!