Ballerina Sweater

Unfortunately no where is there a size chart or description of what these sizes mean. I bought an XS thinking this is meant for toddlers and would fit like a 2T. It’s was just delivered today and is as cute as can be but unfortunately is a final sale item and the worst part is the tag says 0-6 Months!! Why would that not be listed anywhere on any of the children’s sweaters so customers don’t have to guess and be stuck with the wrong size.