What you say is certainly true in the abstract, but real systems, whether they be physical or financial, tend to follow relatively simple (albeit noisy) models. But I don't think the OP's system is even a real system; I think it's likely to be a very simple model of a system, probably involving exponential growth.

But all of this is guesswork. As others have said, the OP would probably get a great deal more help if only he would supply more data.