Period after stopping BCP

How long did it take you all for your period to start after stopping birth control prior to your IVF cycle? I took my last pill yesterday morning after being on it for about a week and a half, and nothing so far. Last IVF cycle it started about 26hrs or so after my last dose so I was expecting it earlier. Now I’m worried because my baseline is Friday with intent to start stims Friday night and I don’t know what they’ll do if my period hasn’t started yet...