Turbo tax asked if my inventory changes. i said yes. but it was actually asking if i want to change the method. how do i change it back? i'm on the web version?

Using TurboTax Online, you can edit (using the pencil icon)  your Schedule C business and look for Inventory under the Expenses category.  Then edit the Inventory expense to go through those questions again.  

There is not a way to preview any of your tax forms other than the Form 1040 if you are using TurboTax Online.  The Forms viewing option is only available through the desktop versions of TurboTax.

After the TurboTax Online fees have been paid, you can print/preview any of the forms by going through the Print Center.