How to track your periods?

I know the question may seem crazy, but I have PCOS, leading up to being diagnosed I went 10 months without a period. Now that I’m taking the proper medication, I just recently started to get my period every month, but they do not come on around the same time that the app predicts it. Before my period I usually have light pink/brown spotting and then it gets heavier. Should I be recording the days when I’m spotting or should I record the heavier days????