Hi ladies!

I had unprotected sex 21 days ago and took a pregnancy test today, which was negative. But i’ve read a few things that have said that you’re supposed to wait until after your missed period or a certain amount of days after ovulation to test. Does that matter if it’s already been so long since I had sex due to me having it a few days after my last period? I guess my question really is if it should be a clear answer by now saying how long it’s been since I last had sex. My period is due in 3 days.