Umm... How impt is gasoline for a car???
LOL, ok..
Bro it is very impt. I would say to grow give yourself 1.5 to 2X your body's weight in grams of protein, protein makes you grow.
As yo where to get it, that depends, you really need to look around, you can get it everywhere. DPSNutrition.com is good site I use for supps, but never used it for protein, they might have good deals though. Do some more searching on the site, I am sure you will find more info.