Problem of the party dress before wedding

After 3 months is my best friend’s wedding. We’ll hold a party and surprise her.

I found a perfect dress that I think is "the one." The only problem is it is online. The price is perfect, everything is perfect about it except I can't see it before buying it or try it on.

I really want this dress. Any advice?

http://www.ambersbridal.com/a-line-off-shoulder-scoop-floor-length-...