I love that dress and you've gotten some great positive advice from lily and skimom
I just want to mention that if your girls are large for your body frame, you'll have to make the darts wider which would then make you have to adjust the side seams and the empire seam. A thing I don't like about darts - they're like arrows pointing to... anyways, have you ever made a dress with princess seams? Darts can be turned into princess seams. Does your dress pattern have a side zipper?
(example of a dress with princess seams - I blocked out the advertising but this pattern is on sale
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