Im behind in credits. Im a freshmen in highschool

I was informed that I am behind in credits. My grades arent bad but they could do better. Can anyone tell me why I am? My grades are : Algebra: 81 History: 90 Biology: 87 English: 91 Health Fitness : 80 Personal Fitness: 87

Submitted March 26, 2017 at 11:02AM by Someguywhocantclimb http://ift.tt/2ok9gQc