What Is The Average Age For A Girl To Get Her Periods?

i am 14 and have not started my period yet; you see 7 months ago; i didnt have pain or anything just normally woke up and had brown discharge! i thought this was my period but it never came back! just a 1 off thing of brown discharge; it didnt even last a day; i just woke up; saw it and obviously changed then nothing! And theres been still nothing for 7 months; so i am wondering could i have an infection? since way before the brown discharge thing i had been getting normal clear discharge and still do now.