Listen to all these guys Limby. When your new to the game, it's easy to become overly inundated with tons of information from different places. Sometimes it becomes difficult to know who you should listen to. The vets on this board now their stuff!
It is ALWAYS suggested that you run test for your first cycle. 500 mg a week split between two injections is the most commonly recomended dosage (assuming your not running test-prop).
As mentioned earlier, the primary reason for this is that most would agree that test should be the "base" of every cycle. Hardly is a cycle ever run where test is not in it. As you gain expereince and knowledge by hanging around, you may choose to add other AAS to the test base in later cycles. Remeber, for now though, that more does not equall greater gains.
Deca specifically is known to shut peoples natural test down hard. It's unique halflife makes it difficult for even expereinced users to time PCT appropriately. Thats why most users who have had previous expereince stack it with test and run the test a couple of weeks longer than the deca. This technique minimizes the chance of the dreaded "deca-dick"!
This is even more reason not to run it alone or at all for anyone's first cycle. It's not worth taking the chance of being in TRT at your age for the rest of your life because you have developed secondary gonadism. Plus, whats the point of all the gains if your just going to lose them all. That's exactly what would happen if you ran Deca alone. You would get big, come off, not be able to get off (maybe permanently), and then lose all your gains.
Listen to the people on this board and read the sticky's. Run test only and get all your supplies BEFORE you start (including PCT and an AI!).
Hope this helps. Not trying to beat you up or anything. Just trying to give you some good solid advice.
btw - many will say your to young anyway. Especially Crazy Mike! lol. I'm just assuming your mind is already made up.