If you want to misconstrue me as portraying a simple, unilateral causal link from menarche to consent, or from the physical to the mental, I can't stop you. My take is more complicated than that, and so is the truth. See, e.g., <link>:

"Researchers have also linked hormonal changes at puberty and increased sexual/emotional arousal (Brooks-Gunn et al., 1994). However, higher levels of androgens in adolescent females were not related to higher rates of sexual behavior, but rather were predictive of their anticipation of future sexual involvement. The best predictor of coital behavior in these girls was whether their friends were sexually active or at least supportive of sexual experimentation (Udry, Talbert, & Morris, 1986). More recent research continues to support a mediated model between puberty and sexual behavior (Udry & Campbell, 1994; Halpern et al., 1997). In other words, hormones may enhance feelings of sexual arousal in adolescents but how they act on those feelings is very much determined by multiple internal and external variables."

So the physical, mental, and behavioral are connected but mediated. And again, I'm talking here about arousal, not about cognitive or emotional maturity. Those are separate, albeit chronologically related, transitions.