You may have entered in in the wrong place. If you are using TurboTax Self-Employed you will have the following screens.
What if you're using Deluxe? Why would have to do special self-employed version for a side gig? What happened before self-employed versions were out there?
TurboTax Deluxe, Premier, and Self-employed all support Schedule C, but the complexity of the Schedule C that is supported increases with each version of TurboTax.
This is because the amount of work that goes into creating the tax return with a sole proprietorship is more more than a simple return that is only a W-2.
NOTE: Deluxe and Premier supports only the very simply sole proprietorship, typically one with few or no expenses.