Ivf using donor eggs

We are starting ivf using donor eggs, anyone who has been through this I have a question that might sound silly but

I have a 26-27 day cycle, they have told me I will use patches from day 1 of my next period and on day 15 I will have a scan to check lining, then I will start on pesories. My husband will produce his sample and all being well 5 days later the embryo will be transferred. This will be around day 21.

My question is could my period still start on day 26-27 ? I would of still ovulated so what happens to that ?