TurboTax provides an estimate based on averages.  The IRS says 9 out of 10 filers who efile and choose direct deposit will get their refunds within 21 days. That still leaves a considerable number of people who do not.  Some returns take longer for additional processing due to specific items in the return.  Some are pulled at random for more thorough investigation.

If the IRS "Where's My Refund" tool at https://www.irs.gov/Refunds shows that your Federal return has been processing longer than 21 days, you can either wait a while longer or phone the IRS to see if you can learn anything about the delay.   

IRS:  800-829-1040  hours 7 AM - 7 PM local time Mon-Fri

Listen to each menu before making the selection.
 
First choose your language. Press 1 for English.

• Then do NOT choose the first choice re: "Refund", or it will send you to an automated phone line.
• Instead, press 2 for "personal income tax".
• Then press 1 for "form, tax history, or payment".  
• Then press 3 "for all other questions."
• Then press 2 "for all other questions."  It should then transfer you to an agent, but there is likely to be a long wait.