Yes, there are two steps you can preview your map and data before you finish.
1. On "Preview" step, you can review your data on the map. It is recommended that you verify the location of your data points
2. On step 6: "Review and Finish", you can click the "Review" button to open a page which is exactly as same as your final product, including the map, page title, page description, and the invitation code. Sharing is disabled for this URL. After you click "Finish", the page may be shared.