This also applies if you are a small, junior or petite size in womens clothing. Sometimes it can be less expensive to buy large or Xlg clothing in the children's section. :
Do UGG Boots Run Big or Small?
UGG® Sizing Information | UGG® Official
UGG® Size Chart | UGG.com
UGG® Tasman for Women | Sheepskin Slip-On Shoes at UGG.com
UGG Women's Judith, Cloudy Grey Leopard, X-Small at Amazon Women's Clothing store
UGG® Women's Classic II Short Boots - Macy's
Ugg Women's Coquette Slippers | Premier Outdoor Apparel, Camping & Hiking Gear, and Footwear