This adorable cardi looks like a scarf is being worn with it but it is attached and draping. It has adorable elbow patches and coordinating wrist cuffs. This is a new style and the sizing appears to run true to size.
A child approx. 18/19 lbs. 29" prefers 6/12 months (12/18 arms are long and lots of room to grow).
A child approx. 33 lbs. 38" in most 3s prefers the 3T.
Older girls if they are tall often prefer to go to the next size for arm length.