Late period

So I started birth control on April 1, 2019. It’s now April 21, 2019. I had sex yesterday, April 20th, (unprotected, it was the first time trying it we just wanted to see what it’d be like since I’m finally on birth control). I was supposed to get my period April 19th, 2019. My first placebo pill is for today tho, could that be why I haven’t gotten my period? I haven’t had sex before yesterday.

Btw I’ve been having all the PMS symptoms so I really thought I was gonna get it on time but I still haven’t gotten it!!