When to test

Hi everyone ! Brand new to Glow and charting so sorry if this has been asked a million times. My period is a little irregular but I usually about a 39 day cycle. I did ovulate this month and BDing seems to have happened at the right time. I'm 7 ish days from my period. When do you test ? When I went to my doc to say we were trying he said they don't test till you're 3 weeks passed a period due date. That seems so long !!!