With my 1st baby I lost my mucas plug and went into labour same day and had him by next day, but I do know you can walk around weeks even months after losing it.. Everyone is different. X
I'm no expert, but i do know that you can walk around weeks before going into labour after losing your mucus plug, but it can happen sooner too.
If your contractions get consistent and timeable, and you think it's the real deal, just go to the hospital and explain your situation, that you are sveduled to have a c-section but you think baby is coming now. They 'll know what to do. You can still have a c-section even if you are in labour, it happens so often. Don't worry to much, all will be fine!