I don't have my 2017 W-2s yet, will I have to start all over again if I stop here?

[xmasbaby0]

Employers have until the end of January to provide your W-2's.  As DoninGA said, just save and sign out, then come back when you have your W-2's to continue preparing your return.

[DoninGA]

Your tax data is saved as it is entered when using the online editions.  Click on Sign Out in the lower left of the program screen.  Just remember your user ID and password so you can return to your account at a later date.