TTC but... I’m confused

So I’m TTC my second child. AF is on time every time and is completely predictable. 4 1/2 days... starts early the first morning.

Today it’s supposed to start. But last night I had sex, unprotected, no contraceptive.

Obviously it doesn’t happen within a few hours and WHAM you’re prego.... but I’m confused why AF hasn’t started yet. I actually thought she would come early due to the penetration last night. And that’s the only time I’ve had sex in months 😂

Gonna stay on top of it to see if she’s coming later or tomorrow .

It just caught me by surprise why she didn’t say hi this morning like usual 😂