Alright so I'm petite, bra size 30DD, and I buy all my tops, jackets, and sweaters in size XS. I got this beautiful jacket in size XS and it fit too tight. I managed to zip it all the way up but it squished my breasts so not only did it look weird but it felt uncomfortable and I couldn't breathe right lol! Anyways, I'm sure size Small will fit better, I hope. Keep this in mind if you're busty.