Is this normal at the start or at any point of my period?

So my period started yesterday, with some brownish residue that came down that indicated I was about the start my period, sure enough later that day it started with a regular blood flow. Earlier today I inserted a tampon and the proper number of hours later I removed it and actually took a look at it before I threw it out. It appeared to have obviously blood on it and some brownish residue towards the bottom, a substantial amount not like all over but enough for me to notice. The residue didn't have a foul smell (I know it sounds gross but I was kinda worried so I did do the smell test) or anything but I am worried it could be something serious? Im 17 years old, not sexually active, I take good care of that area, I bathe regularly and clean it properly, etc so is this normal at the start of my period? Im only on my first full day. I read somewhere this could be a sign of like polypos or something like that, basically tumors in the uterus...Im kind of scared.