Luteal Phase Question

Hi ladies! So my husband and I have been trying for 15 months. My progesterone levels and HSG came back fine and so did his sperm analysis. I decided to go back through glow and it seems that from the last day of my fertile window (last green day) to the start of my period is pretty much consistently at 9 days. Should that be cause for concern? Beginning to wonder if that's why I'm not conceiving. Any info or tips are appreciated!!