Its time to end this gang mess.
And yes, all of them should be considered as adults.

Only the 16 year old to be tried as an adult? Why? The others are old enough to participate in an armed robbery, they are old enough to be tried as adults. The leniency of the criminal justice system breeds this kind of crime. With no fear of punishment what is to deter these preditors from robbing and killing? Nothing!

At the age of 15 & 16 these people have already decided that it is easier to rob and steal than it is to work. So they get a gun and rob a pizza driver. What if she had tried to resist or to run? The assumption has to be they would have shot her. She is trying to work and earn money and those who put her life in danger will be treated as minor offenders.

Now is the time to get their attention. Try them as adults sentence them to 25 years at hard labor (and make sure the hard labor is enforced)with no option of parole. If in that period they decide they do not want to be punished any more; perhaps they will attempt to rehabilitate themselves. In this they might just become a contributing member of society, instead of a parasite feeding on it. But they should not be allowed to say "I am just a kid" or next time some innocent person could lose their life.