NWOT Adidas Game and Go Navy dress

Navy game and go sporty dress. I bought this from Nordstrom, pulled the tags off to wear and was too big. It fits like a medium or size 6/8 vs a small/size 4. Never worn except tried on and never washed. You can see in one of the photos that it runs big under the arm, my mannequin is a size 4. Brand new and cute comfy dress!