Thank you for your query.
The age of menarche
may vary from individual to individual. It is no harm to consult your doctor or pediatrician
who shall assess you regarding your growth and advise you accordingly.
Regarding panty liners, you can certainly use them. Whether they are liners or tissue or pads, the purpose is to absorb the discharge. You need to change them whenever they get soaked. As you have a problem seeking your mother's advice it is best to talk to her parents or your doctor who would guide you day to day.
I hope I have responded to your query to your satisfaction.
Wishing you all the best,