Minigynon 30 ok to still start the next pack?

I just finished my very first pack of minigynon 30 almost three days ago n my period havent started as yet. Im sure im not pregnant because during the past month i was not sexually active any at all...However i want to start a next pack tomor..How long before the pills will be effective and what if my period should start tomorrow, would it b ok for me to still start the next pack or should i wait until after my bleeding?..Im desperately in need of help..Please hurry!..Thank you!