You can do it! If you want something badly enough it can happen, just check out the seams to make sure they can be let out a bit just in case something out of your control happens, like a plateau!
When I first became engaged I tried on a wedding dress and was a size 22, three years later I ordered my dress in a size 14, which then due to further (accidental) weightloss had to be taken into a size 12. I had a modesty panel made for the back which was 20cm wide, on the day the widest part of my lace up back was 7cm!
Remember you will be a stunning bride no matter what size you are. When I walked down that aisle I was so happy I wouldn't of cared if I had to wear my undies to get married!!!
Good luck with your journey