How the checker counts
Google's rule for new personal accounts is at least 12 testers opted in to your closed test for 14 days in a row. The checker treats the day you first had 12 opted in as day 1, so day 15 is the earliest day the requirement can be complete. If your count fell below 12, it starts again from the day you were back at 12.
Play Console's own counter on your app's Dashboard is the source of truth. If it shows fewer days than this checker, trust Play Console and keep your testers opted in.
Questions
When do the 14 days start?
In practice on the day you first have 12 testers opted in, not when you create the track or share the opt-in link.
What if a tester leaves?
If you drop below 12, the streak can break. Recruit 15 to 20 instead of 12 so one drop-out doesn't cost you days.
Does this apply to every account?
No. Only personal developer accounts created after November 13, 2023. Organization accounts can publish without it.
Do testers need to open the app every day?
The hard rule is about staying opted in. But Google asks how you tested and what feedback you got when you apply, so active testers with real feedback make your application stronger.