There is some incremental responsibility already. (In the US) You can drive a car at 16. You can vote and buy tobacco at 18. You can buy alcohol at 21. Not to m

There is some incremental responsibility already. (In the US) You can drive a car at 16. You can vote and buy tobacco at 18. You can buy alcohol at 21. Not to mention, there is such a broad range of maturity in people at different ages. It doesn't surprise me that we have a bit of a hodge-podge.