Shirt is MUCH smaller than expected

The print came out well, although pink continues to be a challenge to get as I intended, but it passes. The main issue is the shirt sizes. It said they were athletic fit, so a little more tailored but it's much too tight, and 100% cotton means it will shrink over time even following wash instructions. I think the sizing guide should suggest strongly people go up a size. The shirts I have simply are too tight to be comfortable.