21 days is an estimate only. The IRS is woefully behind processing returns this year. On the IRS website, they only confirm that they have completed all error free returns received through March. As long as there are no errors in your efiled return, it'll probably take only a few more weeks or a month, but if there was an error any sort, it could take awhile.
Turbo Tax has no control only how long it will take to process. just be patient
