Has anyone experienced implantation bleeding? I didn't have it with my first 2 pregnancies. I'm on…

Has anyone experienced implantation bleeding? I didn't have it with my first 2 pregnancies. I'm on cd19 and my cycles are normally 26 days, I've got brown blood when I wipe, not very heavy but noticeable, I'm hoping its not af arriving a week early. What are the chances this is implantation bleeding?