Wait until you're at least a day or so late. I tested when I was 2 days late and got a positive result. Testing early can give false results sometimes, so i'd try to wait :)
Also, finding out that early makes it seem so much longer, I was 4w4d when I found out I was pregnant, I'm now 24w3d and I feel like I've been pregnant forever LOL. But its starting to get awesome now bc I can finally see and feel my lil man move! I am small as far as a baby bump, but he is perfectly healthy :))
I personally would wait until your missed period. Good luck!!!