What increases estrogen levels in females? Do estrogen levels have an effect on puberty?

Releasing hormones. Females have a baseline low level of Estrogen that comes primarily from the ovaries. As puberty approaches, a stimulus from the pituitary gland triggers follicle stimulating & luteinizing hormones. The immature ovary begins to form signal receptors which will in the presence of FSH/LH trigger more estrogen production. This estrogen advances physical pubertal changes & moves eggs toward release.