Decode 1.8 Strapless Beaded Dress Size 6

Was worn once for a middle school grad Royal Blue Strapless Lightly Padded Fabric tag was taken out but dress is 100 % Polyester Zippered Back Very pretty dress In great shape , couple of loose sequin at the back that could be sewn tighter ( shown on last pic ) Approximate Measurements Laying Flat Waist 15 Pit to Pit 16 Total length 28