Normally I take the stance of "screw em" on this type of questions, but I do kind of agree that taking away the possibility of parole seems too far in some cases.
For starters, I think it's time they officially lower the age of "minor" (I know some states have already done this for certain crime). I think 16 is plenty old enough to make the right decisions, especially when it comes to major crimes.
After that, I don't see the harm in allowing someone to take a look at the case sometime down the line as long as they stick firm to a minumum sentence (if it's no parole for at least 30 years, don't give them after 20 for good behavior or something). IMO, if you are going to give a 13 yo a life sentence with no possibility of parole, you might as well just kill him and stop the pretenses.