Dont you think those 6 girls who beat up the teen are being sentenced a little harshly?

I mean the possiblity of LIFE IN PRISON? Are you serious? Tried as adults. I am sorry but everyone knows that unless you are in you early to even mid twenties only then is your brain FULLY developed. The part of the brain that comprehends consequences is very underdeveloped at any point before AT LEAST 18 years old. But even 18 is kinda eh. So my question is who agrees with me these girls are being treated a bit harshly just because they are getting so much media? Dont get me wrong what they did was WRONG! But honestly, wouldn't a month in jail and a couple years 2-5 of strict community service do them justice? These girls are just now at that point where they are questioning things and finding themselves. They are confused, they don't know who they are yet. I am not making excuses just saying LIFE IN PRISON? Come on even a couple of years in prison is understandable.