Wtf is Cycle Day 1? 😂😂

Okay ladies I know what CD 1 is, however I want to know when my CD 1 is. Yesterday 4/9/17 at 3PM I wiped and there was light blood. I put on a panty liner that was half full after grocery shopping. Changed to a pad once I got home at 6 and I was abt a quarter size of blood on the pad. So was that CD 1 or is it today now that I'm fully flowing! Thanks in advance for your replies!