Congratulations! You've just made a very wise and exciting decision. To take the plunge and engage a design professional.
But like all specialists in their field, designers need to understand what outcome you are wanting to achieve to serve you best, and you need to provide your project's direction. By taking a little time now to think through your 'must have, and would really like' lists, you are way ahead of so many others who are embarking on a similar journey.