What are the symptoms of low estrogen in girls?

No symptoms: Before they begin their period, girls have menopausal levels of estrogen, but have no symptoms. Once a girl begins having periods, her estrogen may rise and fall erratically for 1-2 years before stabilizing. Around the age of 16, a young woman should have fairly regular cycles. If they are particularly light, or they don't happen at all, she should be evaluated for low estrogen.