If i accidentally put that i am a child with investment income , which i don't have, how do i get it off my return?

If you have form 8615 in your return, you can delete it.

If you are using:

• TurboTax Online: see How do I view and delete forms in TurboTax Online?
• TurboTax Desktop:
  1. On the top right, there is a FORMS button.
  2. Click on FORMS.
  3. Locate the form you want to delete.
  4. Click on the form name.
  5. Below the form, bottom left, select DELETE FORM button.