Bikini

Hi all! Need opinions. I found this really awesome bikini in the VS catalog that I want to get. The biggest dilmena I have now is, what size do I buy? My weight loss is slowly progressing, but by summer, not sure I will be at my goal. Actually I know I won't be, but I should be getting closer. Do I buy what size I plan to get to or do I buy what would be the next size down for me?