Predicted But Not

So I got my first period on March 5, this year. I had gotten a brown mark in my underwear a month before(it wasn’t poo) and my mom had gotten hers at twelve, and I was getting emotional. But I totally wasn’t expecting it! I knew I would get it soon but was hardly prepared!
So my mom was signing my sisters up for soccer, she and they were gone. My dad was at work, and the only other person home was my sister. (We are homeschooled) so I went to the bathroom, and noticed nothing in my undies because they were black. But when I wiped, a thick gooey red blood covered the tp! So I put on a thick panty liner(the only thing I had) and ran downstairs and told my sister,shakily. I started crying as she called my mom to tell her. My mom was on her way home, and my sister had given me one of her pads to use.
It was all fine after that.
The weird thing is, I got cramps on the last day of my period!:/