Early period?

Sooo I have a thing, Sooo I'm supposed to get my period in 12 days, but I stared bleeding today. It's very light like I always do right before starting, but I've never gotten my period so early, its never been sooner than a day, anyways.. Is that normal lol my mind rushed to implantation bleeding because my husband and I have been trying so hard to get pregnant lol but with my son, my implantation bleeding was like 4 days before my missed period. Anyways any idea of what it could be.