I love that the pocket on this tee is an embroidered monster pocket! Vintage 1997 Cartoon Network Scooby-Doo burnt orange longsleeve tee in excellent vintage condition. Size large, definitely pretty big like 8/10 or 10/12 as my guess, though go with the measurements to see if it would work for you! Can be worn big on a smaller kiddo, I have no experiential knowledge of having a kid this big yet!
Shoulder to hem: 21"
Pit to pit: 18.5"