Well you mentioned the number twice in your 10 word post so I thought you felt it was significant. FWIW, there usually is a big difference between being arrested as a 17 yr old and an 18 yr old. Seventeen yr olds usually get treated as minors although for major crimes they are often tried as adults.
Lately it seems they are treating crimes by minors in the 17 yr. old range on an adult level. I don't quite understand your point, but mine was not regarding the age, rather, it was regarding the punishment vs. the crime as well as the YOUTH of the offender.
It appears that at the time of sentencing this person was 18?
Regardless of the age, the sentence is ridiculous.