Here is the best advice I can offer you as a stylist:
Pick a style that will hold! The style you picked is lovely, and will compliment the dress very nicely...however, the loose styles like that tend to fall quickly.
Your wedding day is going to be a long one...and you will never have a camera on you more than you will that day...so you want to select a look that be as beautiful in the last picture as it was in the first.
Try to pick something with more stucture for your natural hair...you can have the romantic look with more stability. If you want to play into the backline of your gown, consider using a pre-constructed clip extension. Pre-constructed clips can be purchased with waves or curls that were boiled into the hair, meaning they will stay all day and never lose shape...plus, the nice thing about using a wavy extension is that no ammount of dancing or sweat will loosen the curl.
I think it would look great with your dress, but I have to agree with Italia (because she''s the expert) that it might not last through the day. Maybe you could take the pic to your stylist and tell them to tweak it so that it''ll last longer. They can probably give you something with the same feel but a little more structure.