I think i had my first period..?

Im only 12 years old i haven't had my period yet, but today at school i felt this funny feeling down there, i thought it was nothing, i had a really bad headache and just a little bit of cramps.. when i got home i went to the washroom i didn't pee any blood but in my underwear there was a brown skid mark not to long and didn't smell bad, it wasn't discharge, im also wearing a pad and no blood on it.. so is this my period..?