Going off nexplanon

Ashley • I am 24 years old engaged to the love of my life. We have 1 daughter n a step daughter.
I got my nexplanon implant taken out may 13 didn't have a period for the 5 months I had it in and my fiancé and I are now trying to get pregnant but I don't have any date to base any periods off of now. I know we can we pregnant right after it being removed but how am I supposed to know if and when o become pregnant?