It's hard to say how long, though normally most women will get accurate results after they've missed a period. If your periods are regular, your next would be due around the 12th this month as well. You could try testing with first morning urine from the 10th on up (with a good sensitivity test) and see how the shows. If it comes up negative, you could also make an appointment and request blood work. It'll show an accurate result sooner. Best of luck you!
best wishes to you!as they say,miss your af first then test.
If my miss your period than do a pregnancy test. If negative wait a week and if still no period retest. If still negative than contact your doctor and request a blood test. I hope you get your BFP soon!
Two or three days after July 12th do a pregnancy test it may give you 100% accuracy.
Baby dust on you.
Take care.