You can never know the future. Things will change, and trying to plan for all possible outcomes is impossible; it is destructive, stressful, and it distracts from what you are doing in the present.
And most importantly, do not be afraid to change your future plans; if how you feel, and what you want, changes, then it is time for a new plan. Know that the plans you make right now are not written in stone; pursue your dreams with vigour, but do not be afraid to ask yourself: "Is this still what I want?" It is one of the most important questions you can ask yourself! Do it often, and listen to the answer!