Discharge before period

Okay so I have been having a weird discharge right before my period I don't believe it's spotting because it's more of a darker color, and I only really notice it when after wiping when I pee. I have been to my gynecologist and she has told me that women can have old blood from their previous cycle. It's just weird to me because I never known if that's the start of my cycle but I usually take the date of when I am literally flowing as the start date. Just curious if anyone else experiences this??