Opinions on missed period

Hello, so I love this app because it helps so much with tracking my period and everything, this week I knew my period was coming up and well I'm going on 4 days late, my periods are regular and always start when I should. For me being late this is a good thing considering I'm trying to for a baby. But I haven't had any symptoms or anything to be concerned about, I know it's early to tell but is there anyone who has had experience with this that would give some opinions? :)