Hi, welcome to health care magic
The brown discharge you saw may have actually been blood, this the most common cause of brown vaginal discharge
. There are infections that can also cause a discharge but the color is usually different (e.g yellow white discharge seen in yeast infections
, yellow green discharge that can be seen in trichomonas,gonorrhoea
which are sexually transmitted infections).
This may indicate that your period will soon be starting.
In adolescence periods normally start about age 12 1/2 or by age 14. Delayed onset of periods is only investigated if it does not occur within 3 yrs of breast development or by age 16.
If any of these occur your parent or guardian may consider a doctor visit.
I hope this helps