This seems like a harmful way of thinking about people and development. There's only a limited amount of time in life to gain experience. A 15yr old's brain is

This seems like a harmful way of thinking about people and development. There's only a limited amount of time in life to gain experience. A 15yr old's brain is quite literally not fully developed yet, expecting someone to have chosen and begun studying in their specialty then is ridiculous. Such an early start also not generally possible without the privilege of good mentorship. There's also reason universities historically wanted well rounded individuals and require general education classes--you'll end up stunted or miss opportunity for cross pollination otherwise.