Depending on where you get your dress, it could take several months for your dress to be ordered and shipped. From then, you'll need several weeks for your seamstress to make alterations. You should start shopping about 9 months before your wedding, but preferably sooner.There's nothing wrong with beginning early, even a year before you'll actually place an order. But don't make the mistake of buying yet.ow to Shop for a Wedding Dress. Now that you've already decided what you're looking for in a wedding dress, you're ready to hunt it down and make it yours.