No mentrual flow..
Often girls at age 12-13 are starting to have their period--often about same time or a bit earlier than mom when she had it.
So, it you are of age and having symptoms of a period such as monthly cramps/pelvic fullness/bloating etc...U r 21 n if no period yet, u may have it. A simple speculum exam by your doc/nurse can tell you this. There r other causes of no period. Consult doc. Good luck.