At the same age I was pretty much the same, but then, much later, I realised that I was useless at programing, but that 3D modeling and animation both came 'easily' to me, and were very enjoyable.
What i'm trying to say is that you should identify your talents, and what you *really* enjoy, and hit them like the fist of an angry god. If this isn't coming to you 'naturally' even at this age, then it would lead me to belive that it's more of a 'I like computer games, so I want to make them!' kind of thing. I was the same.
To do such a thing really needs a passion for it on many levels, so what i'm also trying to say is that the first step to doing this is to find out if you REALLY want to do it, which will likely become obvious somewhere between the age 16 and 18.