brown blood is old blood so it just be your body getting rid of what was left over from your last period before this starts. Even so I would wait another day or two and if your period still hasnt arrived properly then I would take a test with first morning urine and see what that brings up :)
good luck and keep us posted
It happnes to me. kinna "TRICKY".. but just wait for couple more days, then take a test. i exprienced with the same light brownish disc. for a day, then it got bigger n' bigger finally Af came. i think its kind of some hormornal change or sumthing, for those who ttc. !!! Hopfully You wont get AF insted u will get BFP :) so Good Luck !!!