TurboTax used to keep a running tally of estimated refund. That feature is gone this year. Why? This is a real downgrade.

Yes, the refund window will appear after you enter all your income and review your tax return. Until you have entered your entire income, all your deductions and credits, the refund isn't accurate. 

The reason for it remaining hidden in the early stages of preparing your return was that it was driving thousands of questions about why it was changing.