CD 13

Lindsey • 🌻💛Lindsey🌻💛
I NEEED some advice! So I'm on CD 13. Today was day 3 of my fertile window. STILL NO positive OPK. I have been testing morning, afternoon, and night. We have still BD each day. Is it possible to ovulate late ( CD 18,19,20)? 
Please...any thoughts or personal experiences would be greatly appreciated!