Initially cycles may vary from 20-45 days and flow can range from 2-7 days and this is mainly due to anovulatory cycles particularly in the first postmenarcheal year. So you can be reassured. Maintain menstrual calendar and give her whole balanced diet mainly iron rich foods and support. Evaluation is required when abnormal menstrual function persists more than 1 year or is associated with other signs like hirsutism etc.

Consult with Pediatrician physically for further evaluation and treatment

Irregular cycles like this are very common in the first one to two years after your first period, since your body is still settling into a regular ovulation pattern, so the on-and-off light bleeding you're describing isn't unusual for your age. A period that keeps going this long, especially nine days or more each time, is worth getting checked rather than just watching it continue.