fit is true to size. Bought this for my 16 month old who will start her first ballet class the first week of December. She's very big for her age and the Toddler size fits perfect (she's in 90% at 31 lbs and tall). I wish the pink skirt matched the pink long sleeve leotard. I recommend you buy this in white, or if you want pink it's more of a pepto bismol pink that doesn't match her ballet shoes or leotard.
I ordered the black skirt for my daughter in the Child size. She normally wears a size 5T or 4/5. It's not too lose but she should be able to wear it for a couple of years. It's perfect for her to wear to dance class. Just enough skirt to cover her behind but not get in the way. :)