My daughter is 20 months old and small for her age (30 percentile). She is wearing mostly size 12-18 mo clothes. But she is wearing this in size 24 months. I recommend to size up. I like it because I think it's really cute, and I love rompers because I don't have to match bottoms and tops. The only thing I don't like is the ruffle at the neckline doesn't lay flat unless I iron it, and I'm not going to iron my toddler's clothes! Next time I would look for a style without the ruffle. The snaps at the crotch are high quality. They are very secure, but not super difficult to pull apart.