When should I consider my period late?

I stopped taking my bc (the mini pill) almost three weeks ago right as my last period ended. I was bleeding every other week while on the pill so haven't have a "regular" cycle in a while. On <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> I was due to start my period Monday but I haven't yet. I don't want to take a test yet because I want it to be positive even though me and my husband aren't ttc and it hurts a little every time I take one and it's negative. I was just wondering when I should really start thinking about a taking a test since I'm "late"?