I looked for a different Natalie child top and found a size chart. Try looking at item N8591C to see the size chart for this brand. My kid normally wears a size 10, which corresponds to a Medium. Hope this helps. - Mytwodaughtersdance (11/19/2013)
The following bust measurements are approximate. This sizing is just a suggestion, sizing is not guaranteed.
Medium: 10" at rest, 13.5" at max
Large: 10.5" at rest, 14" at max - DDS Customer Service (11/22/2013)