Nobody "reviews" it. What do you mean? When you press the "Transmit Now" button it is being sent to the IRS? You should get an email acknowledging that and another email when it is accepted or rejected by the IRS.
TurboTax only gives the general IRS (most returns are processed within 21 days) date. The actual date is known only by the IRS. TurboTax also does not adjust the general date for anything on the tax return. TurboTax receives no feedback from the IRS after filing.
The IRS says most refunds will be issued within 21 days - some faster, some longer.
Each tax return is evaluated on it's own merits. There is no first-in-first-out. Two similar tax return submitted at the same time can have totally different processing times based on IRS criteria for examining tax returns that the IRS does not divulge.
Some returns will be held for ID verification or other verification. The IRS will send a letter if they require more information to process your tax return.
https://www.irs.gov/individuals/refund-timing
Check your refund stratus here:
https://www.irs.gov/refunds
Check your state refund here:
https://ttlc.intuit.com/questions/1899433-how-do-i-track-my-state-refund