First day opinion!!

I am tracking my period to help figure out when I’m ovulating. I have a SMALL amount of spotting this evening but it’s really faint. It is also 3 days late and I probably wouldn’t have even noticed if I wasn’t hoping it didn’t arrive...Should I still track today as my first day or wait until tomorrow when it’s more normal/noticeable?? I just want a more accurate ovulation prediction. Thank you in advance!!