No, you are not required to share your interview. After you finish recording, you'll be given the option to "publish" your interview or to save the interview to your device.
If you choose to publish, the interview and photo will be uploaded to the StoryCorps.me website and they will become publicly accessible.
If you choose to save the interview locally, it will only be saved to your device and it will not be available to the public. We recommend that you backup your interview audio file by exporting it from your device to a desktop or laptop computer (please see instructions here).
While the choice to share is completely up to you, we do hope that you choose to share your interview and have it archived at the Library of Congress. You always have the option to publish the interview at a later date if you change your mind.