Now that you know why you want a lawn, and how big it should be, it’s time to consider what type of grass to grow.
Kentucky Bluegrass still reigns supreme for a turf that can stand up to hard use. It spreads via runners, so it quickly fills in holes. (But beware. Those same runners have a tendency to wind up in the adjacent flower beds.) If you have children and/or dogs, this is probably your best choice.