What will happen if i start my birth control a day before my period is to start?

i'm getting married in july and my period will fall on that day grrrr,i do have birth control pills from a month ago my md prescribed in case i would need to go on bc,but due to side effects i prefer not to take them but desperate times call for desperate measures.so my question is if i would to take the pilll a day before my period is to start and keep taking it through that wedding week,what will happen?will i still have my cycle during that time frame?