For the most accurate fit, please measure your child's foot from the heel to the tip of the big toe and add 1 cm (1/2") for growing/wiggle room, especially if your child is walking. If you can't use a measuring tape, you can always trace their foot on a piece of paper, and then just measure the longest two points. Then still add the extra 1 cm (1/2"). The chart is just approximate sizing based on age, the best way to find the size you need is to measure.
Booties are made of cotton/faux suede/elastic ankle. (I will state if there is any other "non vegan" material in the shoe)
These shoes are my own design, I draw all of the patterns and test and create the new styles before launching them, so you know you are getting something unique, handmade, and full of love! Especially the high-tops... which are my personal fave style! Just so you know, you saw them here first!