Question

I’m not a great expert in the field, but from studies I’ve read it seems that sexual maturity nowadays arrives at a much earlier stage than in the past (apparently because of environmental differences such as nutrition and hygiene), in both sexes (though more so in girls). As for the growth of hair, there are large differences among different ethnic groups, and I haven’t seen a study on Jews, but in all the studies I saw the age is significantly earlier than Rabbah’s presumption of 12 and 13. For example, a large Danish study found that the average is 11.1 for girls and 11.5 for boys.
Does this mean that nowadays, in practical Jewish law, one should not rely on Rabbah’s presumption?