Can I pay for my TurboTax and still edit my return before filing?

Yes, you can.    You can edit your return up until you actually sign and transmit the efile.  And you have print privileges after paying.  Paying in advance also locks in the price.  Otherwise, there will be a price increase in March.

NOTE:  Be aware that once you have paid, you won't be able to use the "clear and start over" feature should you need to.

Here's the best way to pay in advance, by going to the Print Center (you don't actually have to print yet, unless you want to review something).  

• Open your return, and in the left menu column, choose Tax Tools, then Print Center.
• Then choose "Print/save/preview this year's return."
• On the next screen choose to "Pay now".
• The next screen should be an Order Summary.  Review that, and if all is OK, click Continue.
• It should then prompt you for payment by credit or debit card.  The screen only says "credit card", but it will take a debit card.

NOTE:  If it should offer you the option to "pay later" out of the Federal refund, that can't be used for this purpose.  You will need to pay now.

@ vienetta23 

ADDENDUM

I added this to my answer above:

Paying now in advance also locks in the price.  There will be a price increase in March.

@ vienetta23 

I added yet another ADDENDUM  😃 to my original answer above.

Actually a warning:  Be aware that once you have paid, you won't be able to use the "clear and start over" feature should you need to.