Answers:
girl you will most potential know when your bout to start..it sounds close to it might be coming but you can never be sure.. purely start carrying pad...and if you start to identify that everything is annoying...it might be coming
It comes at adjectives different times for general public. It depends on your mass, your physical happenings, what you munch through, and etc.
Trust me, don't push it. When it is time it will come. I not sure how elderly you are, but if you are 14 or elder I would ask your mother or another full-size relatives associate if this is ordinary for your nearest and dearest.