First of all, 16 1/2 inch arms are by no means "huge" especially when they are about 14 inches of fat. No flame intended but bro, you really need to learn about your body and nutrition before you think about starting any type of as.
Get some Ripped Fuel or an e/c/a stack and lose some of that bf first.
And 50 grams of protein a day???? Come on man, you should know you need a lot more than that.
Like everyone else is saying:
Train natuarally for awhile, get a good diet going, and learn about your body for awhile.
You should be in no hurry to start as. If you don't know anything about nutrition, training, and as, then you'll just be wastin your money.
Just my opinion bro.