Confused please help!

Melissa • 33 and trying for my first with my husband Brian.recently moved from palm beach fl to Greeneville TN.
Ok ladies we all use glow so what official day is DPO1 for you?WHEN glow days aren't fertile anymore?? Or the actual day you get a positive day for ovulation?? Cuz I'm either 5 DPO or 8DPO and I don't know which one? Makes kinda of a huge difference gonna look back and laugh one day but the TWW is pure hell!!!