Ovulating late?

Hi there. This is my first month with glow. Cycle began Nov. 23. I've been taking opks since day 7 of my cycle. I estimate a 24 day cycle. They have all been low (faint line) but Glow estimates my ovulation is the 8th. Should I expect the line to darken closer to the 8th? Havent been seeing any progress and have been testing twice a day and it is still very faint. At what point should I expect to see it darken? I know Glow is only an estimation. No ewcm yet. Thanks!