My daugther is 13 her firts period was on may 25 and this month for july she haven't got it yet? and im concern about it

Menarche: During the first year a girl has her periods it can be irregular. Usually it becomes more regular with time.

It happens: Women seldom ovulate during their first year of menses and that leaves estrogen to drive the pattern.Irregularity is common with variations from 2 wks to 90 days in some. When there is a delay, the next cycle is often heavier. When it goes past 90 days some suggest an evaluation to verify the system and work on a treatment that could bring more predictability.