Be sure to read all the comments made by the other knitters who did this little dress. You might spot information you'll need before you decide to knit it...and information that might be helpful to you while you're knitting it!
I always read the comments on a garment before I cast on. It's prevented my from a disaster many a time, especially with regards to sizing and gauge. And sometimes, I've scrapped my yarn choice because someone commented when they used it they were sorry.