When you begin taking piano lessons, chances are good that you wont need to have a piano in your home. But, if you do advance your skills enough, purchasing one can provide you with more ability to practice and become what you would like to become with the piano.
For those that would like to learn the piano but are older, look for specific programs that are designed for adults. You will find that most music schools offer a variety of educational goals for adults specifically. That will give the best route to success.