Recommend ordering one size up. Caitlin wear's a size L for reference, because she likes things a little oversized. 
• 50% cotton, 50% polyester
• Pre-shrunk
• Classic fit
• 1x1 athletic rib knit collar with spandex
• Air-jet spun yarn with a soft feel and reduced pilling
• Double-needle stitched collar, shoulders, armholes, cuffs, and hem

CQ Unisex Sweatshirt