Best way to avoid having my period on these dates?

I'm on the last day(s) of my period. I need to avoid having my period August 13-23 but eve predicts I'll start my period August 12 😭🔫. I have a pack of BC I haven't started yet and I was thinking of starting it a week before my trip so hopefully being on the pill when my period is supposed to happen will prevent it? I'm seeing my boyfriend and we aren't able to see each other for months at a time so I really don't want to be on my period the entire time. I don't care about messing my cycle up.