Purchased this for my 3 year old. Glad I went into store to try it on her first as the age 4 was very small. Age 6 fits her nicely with a little room to grow. She's average size for her age so I would recommend going for the larger size as a few reviewers have suggested. Great price and lovely quality too.
Not suitable (as in not approved by RAD) for exams because of the little bit of rucking at the front, so I had to return, and continued to shoe horn my daughter into her old leotard for a few more weeks. Shame, as price and quality seem spot on.