At 230 I was in a size 18 and now at 155ish I'm in a 10.
I too suggest you wait as long as you can. (I love the first dress! I think it's adorable without being cutsey. A little retro, a little fun.
) Another option to seriously consider is to have the dress custom made when you get closer to goal. I make custom gowns on the side and would be more than happy to help out a bride who came to me with that picture in hand and likely for a price similar to that or less. A good seamstress can work wonders and that dress isn't super complicated.
ETA: But if you do order a dress keep in mind that it is easier to take a dress in than let it out. If there's nothing in the seams there's really not a lot that can be done that will preserve the original design and alterations that involve reconstructing a dress can get pricey. In other words, order larger rather than smaller!