Digital test sensitivity?!

Laura • Straight edge, vegetarian, feminist, lover of animals.
Okay so I just read it in that the digital tests are for people who are further along in pregnancy and aren't as sensitive. 
I'm confused because I got my very first bfp this month  with a digital and according to the app I was only 3w5d when I took them. 
Is it possible that maybe I'm further along than I thought, or maybe twins?