different apps say different days for O- AF due 3/8

so I have 3 apps I follow, I got my last period feb 6th, all apps said that was accurate. then they went wonky and one said I was ovulating the 12-17, glow says 18-24th... so weird but all three apps say I will get my period either the 7, 8, or 10th. we have done it every day so I am not super worried about that aspect, I know we have it our best effort (TTC for 5 months now) but I am more wondering about my TWW! I don't know when the heck to start testing, looking for symptoms, etc.... anyone else in my predicament that apps say different dates?