although my last pg was my 3rd child, it was the first time i had a natural labour so treated like a newbie- also a VBAC
OB had concern that bubs would not engage and be too big to engage and would have to have repeat c/s. No way was i gonna let that happen

The nite before i had him i felt a drop and clunk and pressure in my pelvis- so much that i got out of bed to check that my waters hadnt broke- they hadnt and didnt till i hit transition in labour
cx started 9 hours after i felt bubs engage and i had him that afternoon- 6 hours later.
trust yourself and your body- it will do what it needs to- when the time is right!!!
good luck