You generally cannot know for sure without an internal exam
Strong, regular contractions that are getting closer together may suggest labor is progressing
A feeling of pelvic pressure or the urge to push may suggest advanced dilation
Bloody show may happen as the cervix changes
Loss of the mucus plug may occur as the cervix opens
Increased lower back pain or cramping can happen with cervical change
Water breaking can occur with or without significant dilation
Some people have little or no noticeable symptoms even when dilated
Only a healthcare professional can confirm dilation accurately