Smudgie from what I've read only 15% of labours begin with the membranes rupturing.
I was in labour for 11 1/2 hours before my waters broke.

Contractions went from
8-10 mins apart; 5-9am
5-7 mins apart; 9-11am
3-4 mins apart; 11am - 4:30pm when waters broke
I went to the hospital at 7pm.

I would have been in "established labour" (past 4cm) sometime around 3pm but had contractions steady the whole way through.