Brilliant Bear crew sweatshirt by Grizzly. Regular fit. Brilliant Bear graphic at front. Grizzly x Diamond collab. Diamond logo at left wrist. 80% cotton/20% polyester. Imported.
Whether the men's Grizzly Brilliant Bear Crew Sweatshirt will work for you depends on your body type. I know you told me average, but that could cover a lot of dimensions. My recommendation would be to use the size guide offered online for this garment since these charts are directly from the manufacturer. If you get the chest measurement to work, then the rest of the top should fall into place. My gut feeling is telling me you might need a smaller size, maybe even a Medium.
Most manufacturers will pre-wash the garments so shrinkage is minimal for customers. I can't realistically say how much the men's Grizzly Brilliant Bear Crew Sweatshirt will shrink the first wash, but I can recommend using the lowest possible temperatures during the washing & drying cycles to help prevent shrinkage, especially with the first few washes. The fabric has a lot of cotton to it so any precaution you take will be worth it.