LOL, doesn't work. Your definitions contradict each other. Turn it around - what if the kid had sex with an adult, and then indicated the same level of clarity about sex that he is about murder. Would the DA shrug and say, "well, intent was clear so he acted as an adult so there are no statutory rape charges? Hell no - he would say rather that no amount of clarity could establish adult intent by definition.
Same here. Charging as an adult is a farce. Either get rid of the juvenile laws, or obey them. But a ten year old is out of bounds and the prosecutor is acting shamefully, not to mention illegally. The kid's lawyer should have this thrown out for lack of statutory authority.
It’s not supposed to work objectively. The legal system is controlled by Post modernist Statists, who interpret the law as a means of social justice.