Wedding Dress Help

So, I've found the most beautiful dress online that I've absolutely fallen in love with. Or I had until I showed my mom. Comments about modesty, "your boobs could fall out the side, will you be comfortable??" and the low back, etc have really made me second guess the decision. I love this dress, I think it's absolutely beautiful, but she's really made me gun shy about ordering it. Opinions? (idk if this helps anyone help me: I'm a size 0/2, a 30D so not super busty, really slender. I think last check my measurements are like 33/25/33)

http://i.imgur.com/WwbjbWZ.jpg

ETA: I can't try it on before buying, and short of the super cheap end of David's Bridal dresses, I really can't afford most dresses at brick and mortar stores.