Here in Australia, the legal age for drinking, smoking, voting etc. is 18.
Which I guess would mean that according to the law, you are only considered responsible enough when youre at that age. BUT....
At 15 1/2 you as a child, can choose to leave school.
At 16 you cannot buy pornagraphic material but you can legaly perform anything that is in one.
At 16 you can get a learners permit to drive.
At 17 you can get a provisional permit, to drive and you no longer need anyone else with you.
At age 10 years old I had known for a long time that it was wrong to hurt other people.
No child as far as I am concerned above the age of 10 has right to say that they didnt know that murder or rape was wrong. At that age they definatley know right from wrong.
So yes (in my opinion) they should be charged as adults, above the age of 10.
If not, they should at least be sentenced as adults if found guilty.