Zac and Rachel Nice Black and White Blouse/Shirt

Please see title and photos. Also, this shirt has no size tag???? I have no idea if I’m just being blind, or it really isn’t there. I’m going to guess a small. Whatever the case here are measurements to help with that. Price reflects my lack of knowledge. Arm pit to arm pit- 19” Front shoulder to hem 24” Length from first button to bottom hem-17” Back hem to back hem- 28” Arm length when rolled up - 18”