Menarche has nothing to do with puberty

Visible bewbs and widening of hips happen before the first menstruation,

With respect, that's an incorrect assumption or conclusion.

As I've posted earlier menarche can occur long before a female's internal hip structure widens enough to permit the passage of an infant's head for a normal delivery.

A twelve month old's internal anatomy certainly isn't developed enough to carry and deliver an infant to term (a strange paradox, since it's an infant who's potentially capable of carrying another one), however cited and juried medical references are available regarding the twelve month old I'm referring to.

At least one site has 173 confirmed attributions from around the world regarding preteen and even preschool menarche, pregnancy, and the statistics to confirm such.

LG's as young as five have gotten pregnant, and there's a steep curve related to successful pregnancies and births starting at six.

as must be, given that they are what makes a pregnancy and childbirth viable. Hips by creating the internal space, bewbs by creating the nutrition after birth.

Again, with respect, that's an incorrect assumption. Viability for pregnancy isn't determined by breasts nor hip development, but by the levels of various hormones, such as estrogen, within an infant's or LG's body to develop their ovaries and uterus. Direct links between breast and hip development with reproductive ability can't be substantiated, and enough empirical evidence exists to support what I've posted.

Significant breast development is also a poor indicator, because infants, toddlers, and preschoolers can develop noticeable and well-defined breasts, either symmetrically or asymmetrically, due to a number of potential hormonal conditions.

When a small amount of breast development occurs without the rest of puberty progressing, it is called premature thelarche
(quoted from one of many dozens of sites on the web)

None of the information I've quoted is specious nor exaggerated. I'm very familiar in this area of human characteristics and development.