First period?!

I’m 5 weeks PPT and wanted to start using this app so I can track my periods and use the natural family planning method, as I don’t want to use birth control this time around. however, I am confused as to how to track my period!

I am breastfeeding and was told I may not get my period. So I stopped my post part I’m bleeding at the beginning of the third week, and then at the end of the fourth week and through today have been lightly spotting. Is this my first period?