First month using OPK

B • Eisley Summer 9-10-13 🎀 Owen Kingsley 6-19-19💙

When should I start testing? Glow as my periods at 5 days but it’s usually more like 3 so I want to make sure that I get the right window (I tried to edit my period length and it still says I’m on day 4 even tho I’m not). Should I start testing today since AF stopped last night or should I wait a couple days?