First hat failure

I decided to try my hand at a simple knit hat and boy did I mess it up. It came out soooo small. It was suppose to be child size and it looks like it will fit a preemie.

Here's the pix of the finished (?) hat.

And here's what I did wrong, thanks to the observations of my fellow Yahoo group knitters.I cast on 90 stitches, then I knitted 2 ins of 2x2 ribbing and then started the decreases. It was pointed out to me that I neglected to knit 5-7 inches of stockinette stitch BEFORE decreasing. Wah!!