Hi I'm 13 And I Haven't Started My Period Yet.

Hi I'm 13 and I haven't started my period yet. My mom started her period around my age. Yesterday I wiped and notice brown discharge and a little blood. I'm not sure if this is my period or there is internal bleeding or something I told my mom that I was on my period but not that it was only a little. Today I decided to put in a tampon just in case later today when I took it out there was only a little blood and when I go without a tampon there is none on my underwear.so obviously its not a constant flow. I am having cramps but only mild. Help is there something wrong with me or is this my period?