I know this is probably a dumb question but I've never in my life asked but I'll ask now LoL.......

When clicking on the "I started my period option" on this app or any app do we hit the button as soon as u see spotting or when u officially start your period?

I was 7 days late as of yesterday but late last night I saw a hint of pink on the toilet paper so I put on a pad... this morning there's still nothing on my pad but after I went to pee and wiped I saw a tiny bit of pink again so technically I haven't officially started my period. So do I choose that I started my period yesterday, today or what do I do?