It is important to cover whatever period you intend to include in your personal statement because time spent planning your sequence and the method you feel happiest with will undoubtedly make the actual writing that much easier for you.
Of all the writing, one ever knows 'Personal Statement' turns out to be an unusual or special kind of writing. This is required in many colleges or universities and is considered as important part of the application. It provides an opportunity for the students to express themselves freely and give them a chance to bring out their personality through the writing. This is the statement where one is able to present themselves to the university and also convince the academic officers of the university regarding their ability.