I was told that with No 1 head engages before labour, and with no 2 onward head engages when you go into labour - mine were opposite.
No 1 - head wasn't engaged before I went into labour
No 2 - head was engaged 2 days before I went into labour
so I don't think it is a real indication of when you will go into labour, everyone is different.

goodluck and hope it all goes well for you.