Grade 8 Graduation Dresses/Hair/Accessories?

I need a dress for my grade eight graduation.
I'm 4'11", about 80lbs and verrrrryy skinny. (I have a fast metabilism)
I'm kind of short and not very 'developed'. I have brown skin, something like this: http://www.sephora0o0com/assets/dyn/brand/5877/5877_hero.jpg
I have black hair, it is straight and I have side swept bangs, with short layers. My hair is about 6-7 inches under my shoulders.
I'm looking for a dress around the knee area and I doesn't really care about the style.
I was thinking Baby Blue with no design and I want it to fit snug.
My price limit is about $150.
Suggestions for accessories and hair are greatly appreciated!

Sorry if I'm being picky about this :[
I just love buying dresses, accessories, etc.