How do you count the days?

Usually every month before my period I get a brown (bloody?) discharge. This is normal for me it happens all the time. But, do I document it as spotting or do I say my period has begun? It's heavy enough that it gets my underwear, but it's not pink or red it's brown and eventually after a couple days turns into my full blown period (they r usually heavy). I'm 24 so I'm not by any means new to menstruation, but I am newish to flow and want to make sure I'm documenting correctly. Thanks for your help ladies!!