You usually lose your mucus plug 1-2 weeks before going into labor. Signs of labor include rupture of membranes (water breaks) and contractions which are strong and close together (such as every 5 minutes) and does not ease with walking or resting. These kind of contractions change the cervix. But since your baby is breech, are you scheduled for a c-section? If you are then you need to go to the hospital when you do start contracting on a regular basis because since this is your second pregnancy, you can dilate a lot faster than with your first child. Be sure you discuss these things with your physician.