When should I test?

Isabel

I am about 8 days late on my period, on here it says 10 days but I think it’s off. It’s only been 3 weeks since me and my SO did anything. Could it be too early to test?? I got 4 BFNs. One 25th , 27th,29th , and the 30th. I need help, I have never been late before. I have pcos and was told it would be hard to have kids so I am hoping it pregnancy. I don’t want anymore bad news in my life. I need hope. Please any advice?