My kid loves these. She is petite for her age, but knowing this style of pajamas, I ordered a size up anyway.
 They were just a bit baggy for the first wear, then got snug after washing and drying. (Again, I knew to expect that from this style) After wash number three, she is complaining that they are too tight and we have to go through the ritual of stretching them in front of her before she will wear them.  Aaargh, kids!
* She is 33 pounds and is four and a half. We bought a size 5.
We were really happy to find girl dinosaur stuff, so they were a big hit.