That said, the OP could probably benefit from planning ahead a little more. It helps to focus on core aspects of the product that are not likely to change and to anticipate things that you might want to change. At first, it may be a little hard to hold your entire project in your head at once, but once you've broken it down into a few core components, it becomes much easier to think about things going forward.
It sounds like the OP is already arriving at these realizations, so good luck to him!