Doing TDD without having skillset in writing tests leads to the problem that writing the test first is very awkward & time-consuming, developers then feel that they're spending more time on writing the test than the time spent writing code, and then they get frustrated and blame TDD.
That's why I recommend practicing writing tests (in test last way) so that developers get sufficiently comfortable & fast in writing tests. Then, when they later switch to TDD, the RED step will be straightforward/fast, so they won't feel like writing a test is slowing them down.
Doing TDD (and having never written tests before) is overwhelming!
Doing TDD without having skillset in writing tests leads to the problem that writing the test first is very awkward & time-consuming, developers then feel that they're spending more time on writing the test than the time spent writing code, and then they get frustrated and blame TDD.
That's why I recommend practicing writing tests (in test last way) so that developers get sufficiently comfortable & fast in writing tests. Then, when they later switch to TDD, the RED step will be straightforward/fast, so they won't feel like writing a test is slowing them down.