Peak day 1 OPK ClearBlue fertility monitor

Megan.
Hi all!
I started tracking my O this month and received a positive opk from my clearblue fertility monitor on CD18 and CD19. I also got positive with the Wondfo opk on these days. We BBD on CD18 around 5 PM only. I know there is a low chance of conceiving the first time, but anyone else get pregnant the first time they BBD on their first peak day on opk?