TT ask - What year did your spouse pass away? Not my spouse. My Mom died. How do I change this?

Go back to the beginning of the Personal Info interview. On the first screen after you enter the taxpayer's name, a screen appears asking if any of the following apply to this person. Check the box "passed away before filing".

If TurboTax is assuming this is your spouse, it sounds like you may be using your own account. If you are using TurboTax Online, you will need to set up a different account to file for another person. 

Per IRS rules, you can only e-file up to five federal returns using the same email address or phone number with personal tax return preparation products. See this help article for more information.