normal?

Kimberlee • Kimberlee 💛 Juleeana born 8.22.18 💖💖💖💖
My husband and I have been trying for a month with baby #1. During this month, its the first time we BD'ed without any type of protection... according to a couple apps I'm supposed to had AF already... I have never really tracked it until we started trying. Basically what I'm asking is, is it normal for AF to be late due no protection?