I ordered the purple and a cream color, in the size 6-12 months for my 7 month old who wears 12-18 months and is about 20 pounds and 28 inches long. The upper and straps were way to big and the bottom romper part fit perfect. So my the time the top fits the legs will probably be too tight. That being said they were very cute, the smocking wasn’t scratchy. And they were decent quality!! Had they fit I would have kept them. The colors were cute, the bow isn’t a real bow just a tie for you to make a bow which we probably wouldn’t use. My daughter is big for her age so if your baby is true to size or on the smaller size I would say the size 6 month wouldn’t fit a 6 month. But again cute and decent quality!! If it would have fit I would have orders more!!Fits great, and looks like what’s advertised but it’s very thin & see through