You have about six weeks where you can ask otherwise outrageous questions and actually effect change. After that they will just think you are an idiot.
Yes. this is a better phrasing. The key point is that you can ask almost anything in the critical new window.
After that period the ability to make other people re-think things significantly is made harder by their preconceptions about you, from their shared experiences.
BTW I've been telling new hires this for years, decades even. Not the 'after that they'll think you're an idiot' bit.
I would say, rather, there are no stupid questions.
After awhile it will become increasingly clear who fields questions well, and who doesn’t.
Cultivate the former, avoid the latter.