When starting a new return, the online program transfers information from last year into the current tax year. Since you were self employed in previous years, it is upgrading you to the self-employed version when this data is transferred into the current year. To downgrade you can clear & start over and select "my tax situation has changed" in the beginning of the new return. From there you can select that you no longer have a small business. Below are some steps on how to clear your return if you haven't filled anything in just yet.
https://ttlc.intuit.com/questions/2586254-how-do-i-clear-and-start-over
https://ttlc.intuit.com/questions/2964520-downgrade-version?jump_to=answer_4927602
