Certainly, you can start entering all the various personal data that you have, and if you want to try to guess what your Form W-2 will look like and also any Forms1099 that you might receive, such as Interest Income, feel free to do so for ESTIMATION purposes only.
However, read this post to learn why others have found it to be a very serious mistake to go ahead and submit your filing before you have gotten all your W-2s and 1099s.
Go to this link and learn why the earliest that the IRS will even see your tax return filed is January 23, 2017, and the earliest that the IRS might deposit your refund is February 3, 2017. Go to this https://ttlc.intuit.com/answers/5584013
Read what folks who filed in a hurry had to say last December and January.READ THIS: https://ttlc.intuit.com/questions/3405630