At under 21 I would get you on Slin before high carb/protein meals, Lipotropic Protein 3x daily between well balanced whole food meals and BC+EAA for pre/intra/postWO nutrition.
As Craig said above, I-GH-1 is also another great option when taken before bed to help raise GH levels.
All of these are very reasonably priced/economic supps so you should be able to get a great stack going!