Oh, I had a table of mid-twenties absolutely war-criming the shit out of a slave driver one session, and befriending the lich that was supposed to be their act boss like a half-chapter before that fight was supposed to go down two weeks later. Age is absolutely irrelevant.

EDIT: The fix action for the lich was I pretty much made his 'non-combative' personality into Uncle Death from Let It Die, and the party got a fun 'call in a favor' flavored DMPC to deal with a new fight to take the place of what was SUPPOSED to be the party's lich fight.