Konstantinos I became King on 18 March 1913 and she became Queen-Consort. The original image posted on this page came from the USA Library of Congress' Bain collection and their record for that image bore the date 21 June 1913.
From WGABRY's photostream on flickr; I fixed small spots throughout the image with Photoshop.
The bodices of dresses from this time can be adorned with elaborate embroidery that accentuates the neckline as on Sophia's dress. Her dress appears to have a shallow-vee waist band, but that appears to be an illusion created by the folds of her dress.
Keywords: Queen Sophie of Greece, Princess, Queen, Hohenzollern family, Glucksberg family, Greek, straight coiffure, tiara, sweetheart neckline, modesty piece, elbow length sleeves, engageantes, no waistline, tight skirt, necklace, draped necklace, earrings, brooch, bracelets, fan