Reversible Blue Floral Tulip Dress unbranded

I love this dress! What a fabulous idea to make a reversible dress with simple snap closures. There are no tags and therefore no brand or size. My guess would be around a 3T? Please see measurements (laying flat): Shoulder to hem 21” Underarms 12” Bottom 18” Arm opening 5” This is at least 16 years old and is still in great condition, no major flaws, but, as with all used items, it has some wear.