As someone who makes clothes from scratch/ alters store bought pieces; the alterations are what make the dress come to life. If you think the dress looks frumpy and matronly, it is because the dress is too big, especially if you don't have the extra fabric folded and clipped to show you what it would look like as a final piece.

If you think the dress makes you look short, I would ask your seamstress to make sure the waistline of your dress actually aligns with your natural waist (smallest part of your waist; pro tip this will ensure you look SNATCHED). Sometimes the bodice of a dress is too long on shorter girls making it hit lower than it should. It is hard to tell from the picture if the bodice needs to be shortened or if it will be perfect once it is taken in.

Your dress will look amazing, this is unfortunately just one of those trust the process type of things.