hi No unfourtunatly a bigger fundal height doesnt mean going into labour earlier . With my older boys I was always WAAAAY over e.g at 36 weeks with my second I was measuring 44cm. He was delivered at 37 weeks at 9lb 10oz by c-section but it was for medical conditions not to do with his size.
It could be the way the baby is lying, his/her size, a slightly higher amniotic fluid level or a combo of all of them causing the bigger measurement.

Good luck with everything you have not got long to go now!!

Melissa