I am starting my first Oliver & S pattern - the sailboat skirt and top - for my daughter. She is going to be 3 in a couple weeks and her height (37.5") puts her in a size 3T, but her other measurements fall in the 6-24 month sizes (chest 20, waist 20, hip 21). Any suggestions for me about what size to make her? And actually, her grandma is making this, not me...!