The Theia set/dress is a made to measure and size inclusive pattern, this means you measure yourself as the pattern suggests and then follow the instructions. This means the pattern can be made for any size or age. The pattern is for the top and skirt that can also be joined together at the waist to make a dress.
The pattern is an advanced beginner level that uses US terminology, it has detailed steps, pictures throughout and stitch graphs to help guide you. You will need any type of 4 ply (fingering weight) cotton yarn and a 3mm crochet hook, I used roughly 1700m for the sample size (small UK).
You will also need elastic (size 2-8mm) which will be used for the waistline of the skirt for the perfect fit and optional for the cuff sleeves.