Would the patch still work if I applied it before my period begins for the first time?

So my period began on Feb 1st, and I got the contraceptive patches just a few days ago. Instead of applying the first one on my skin when my next period begins, I decided to just put it on on Feb 18th, then I had unprotected sex with my boyfriend last night Feb 19th, and he came in me. What is the chance of me getting pregnant during this time period? My menstrual cycle is usually 29-30 days. If I get the emergency contraception tomorrow, will it still work to prevent pregnancy? Because I think my ovulation is already over, and I heard the E.C. is not effective after ovulation.

Thanks.