I was wondering if a teen has low estrogen levels will they develop all the womanly qualities once the estrogen is introduced?

Low Estrogen. Estrogen levels vary throughout the menstrual cycle. If periods are absent, a good first step is to check for pregnancy, then try Progesterone withdrawal. If a bleed occurs, estrogen is likely ok. If no bleed, FSH levels are checked. If high, consider ovarian failure, if low hypothalamic hypogonadism due to stress, exercise, anorexia, or genetics could be the cause. Bcpills may be advised.
Yes. Mother nature will take care of that as you through puberty , unless you have a different reason to use it ?