Authentic Mac cosmetic T-shirt size small

This T-shirt is an authentic employee MAC Long sleeve T-shirt from a collection way back. Fabulous Felines is printed on the back of the shirt. Brown long sleeve crewneck T-shirt. Says size 3-4 it looks like a small to me. It’s in great condition however I did just notice that along the side seam at the end of the hem has come undone. An easy fix, it’s about an inch right on the seam. Excellent condition except for that. Measurements are 18 chest, 24 inches from top of shoulder to bottom hem.