Steps to become a Narcotics Officer?

I want to become a narcotics officer, i live in a place where Meth and all that other stuff has messed up a lot of family and friend's of mine over the years. I live in TN. This is something that i've always been interested in. I don't want my son to grow up in that kind of enviroment. I may have a few things that might disqualify me to be one, I have a prostetic eye. but i am in good health, i can shoot a good very accurate. And i'm pretty smart when i want to be. I have a clear criminal history. I already own a handgun and am working on getting my Handgun Permit. Is ther any goverment funding i could get. cause i come from a very poor family. Any info and More details would be very usuful, i plan on doing all this when my wife gets out of nursing school, and when im a liittle older, next year when im 25, i know noone like seeing young cops. Thanks for looking and reading.