Only the IRS can tell you. Once you submit your return then Turbo Tax is done with their part. The IRS doesn't give Turbo Tax any updates about your return or refund.
It is possible that your return is being reviewed for various reasons. The IRS is carefully reviewing returns that claimed the earned income credit to prevent fraud. So it maybe one of the reasons your return is being delayed. Another reason may be because your information statement (e.g. W-2) does not match IRS records; therefore, an adjustment is needed. There also may be a pending offset towards other IRS taxes or governmental agencies liabilities (e.g. state, school loans, child support, etc.) you may owe.
The IRS will send you a letter, explaining any adjustments that may have been required. It is advised that you contact them by the stipulated date of April 22, 2019, if you do not receive your refund and or a letter explaining the delay.