Ovulation test

So to me this isn't quite dark enough to qualify for a LH surge. (Control window is square) 
Do you think I'm getting closer to O? This is the darkest test I have had.  I have never had a test be positive (though I have gotten pregnant twice) according to my glow my fertility window is closed. Typically I wouldn't have tested the last two days per directions on my ovulation kit. I'm on CD 17. Maybe I O later than the "typical" person?
Any help would be great!