Does Life Really Begin at 40?

I listened to Dr Fadzilah Kamsah motivation tape. He said that women are most beautiful at 40, while men gained their actual maturity at 40 (that's why Prophet Muhammad s.a.w. was appointed to be Rasullullah in his 40s). If this is true, what really happens before one reaches 40? What's next after 40?

For women - aren't we all reached maturity at that puberty age? Some 10, some 12, some 14 years old. That's why at that age, we can see girls to be far more matured in thinking than boys. This is also why there are so many girls in universities in Malaysia. Our Malaysian education system tailored to matured people at young age. Where'd the men go?
Because women reach maturity at such young age, at 40 women appear to have reached a plateau, going down next.

For men - because it is proven time and again that men only reach maturity at 40, the period of "immaturity" since to last very long indeed. Maybe from puberty to 39 years old. That could roughly last about 25 years? But this is the period when a man decides to study or to work, to get married or stay single, to live healthily or sickly, and many more important decisions, which at 40, it'd be too late to reverse isn't it? So do they make decisions with immatured thinking?
Because men reach maturity at 40, they appear to be just starting off their engine to climb up the hill, to face challenges of life, with matured thinking, and therefore, are more attractive.

Conclusion - men and women have different wavelength before they reach 40, but after 40 the wavelength should be syncronized. Or the thinking gap is actually getting wider? Hence, before couples reach 40, what should we do to prepare ourselves before reaching that "40" fence?