There are several issues that I have with this costume.
Because Sophie's costume is considered period, there needs to be more of a period shape to it. The style is closer to Late Victorian - 1890s. I would suggest use of foundation garments to make the correct shape. As the dress is now, it adds about 10-20 pounds to you. You need to define the waist to properly fit that era's silhouette, rather than calling more attention to your breasts, which is what this does. I suggest tailoring it to your measurements with a corset or with proper foundation garments and letting it out if you gain any additional weight. The way that you have it in your pictures is at an empire waist. This is wrong. Empire waists are closer to regency and Mid-Edwardian (if you feel that the Edwardian Period ends in 1919, like I do). The apron needs to also rest at natural waist rather than above.
The second major issue is the dress length. It's way too short to the point of inaccuracy. Remember that this is set with an 1890's aesthetic. While there are a few artistic liberties taken with Sophie, her dress still generally tends to hit the top of the boots. Considering the dress length for young ladies of the era, this is historically accurate for someone who is about 16-ish years old, which is close to Sophie's actual age. I would seriously advise you to NOT use images of her dress billowing in the wind because the animation style there would have you mess the dress up. If you do want the petticoat to show, raise the hemline about a half-inch and use a petticoat with eyelet lace.
The blue color is amazing. A bit bright, but I would think that it's due to the photo style. I still love it. I also love the boots (extremely accurate) and the stocking color. The dress itself is nice and you guys look good and as though you had fun.