Is it normal for a teenage girl to miss period or be late?

Yes, it is normal for a teenage girl to miss or be late for her period, especially during the first few years after her period first starts. This is because teenage girls often have irregular menstrual cycles. It may take a few years for their cycles to become more regular. Additionally, stress, diet, and exercise can all affect menstruation. Talk to your doctor if you have any concerns about your teenager's menstruation.