Pregnancy test


So I’m curious to find out from other women how alearly did you receive a positive pregnancy test before your period was due? A lot apps I have downloaded some say take a test now an others say wait a certain amount of days. A couple <a href="">pregnancy apps</a> I have downloaded says I am 3wks pregnant an I can possibly get a positive. But I’m not really sure what to believe. Has anyone ever tested positive at 3wks pregnant? If so did you have any symptoms? What were they?