I hate feeling like a dummy and having to ask?!

Vivian

Ok I posted earlier about a concern with an upcoming chest x ray the day before af is due. I don't use opks just kinda know my body so to speak but let's just do a broader spectrum. I o'd between the 2-5 app is always correct with start day. so It says af supposed to show the 20th. what is the earliest I can start testing?!