I'll assume you haven't yet selected LIVE. If it's already been selected, or if you end up in it by mistake, we can tell you how to remove that feature.
Try this. First log out and empty your browser history cache and cookies.
Close the browser and reopen it.
Then go directly to this page before logging in. Don't log in until you proceed further, and it asks you to.
https://turbotax.intuit.com/personal-taxes/online/#diy
We you arrive there, be sure to only choose the far left column product. The middle column and right column are both LIVE products.
If you do that, is is still trying to direct you to a LIVE product?