Dreams can never be converted into reality, unless and until they are not converted into goals and goals are nothing but your dreams that you are looking forward to achieve in a specific period of time. When you actually determine at what point of time you want your aim to be fulfilled, your subconscious mind is gearing up the speed and the force to take you into action. The shorter the time you determine to achieve a goal, the faster your mind comes into action to do the same.
However, it does not mean that you allocate unrealistic time-frame to any goal. Doing this would only fade away your enthusiasm towards your goal and possibilities are there that your mind assumes it as a not-possible-goal to achieve. Therefore, before determining the time period, always consider the different aspects of the goal and have realistic expectations from yourself.