How long have you stayed 3cm dilated?

Currently 39+6 and just had my doctors weekly check. I did progress from barely 1 cm to 3 cm from last week, but it was a different doctor in the practice. So, I’m skeptical if they have varying opinions on how dilated.

How long have you stayed 3 cm dilated before labor started? I have no other signs. My first was 9 days overdue and had to be induced so I’m a little stressed knowing I’m already more dilated than last time with baby #2!

All the articles I’ve read say that stage 2 of labor starts at 3cm dilated so I’m conflicted!