It's funny, I remember in all my previous Traveller experience, I interpreted the barbarians they way you all just said, i.e., progressing through ranks 1-5.
But on Sunday, when I had players rolling up characters for my first new Traveller campaign since the T20 playtest, I suddenly panicked. So, we ended up with an 18 year old barbarian chief (peculiar, but actually not completely implausible). It didn't seem right. Not that it matters much, he got an additional skill roll and muster out roll or two, but since he was only a 1-termer it didn't throw things out of whack.
By the way, just how awesome is CT character generation? I mean, I could have sat there and helped my players roll up character after character all freaking night long. It really is just the best.
(I did port a few things in from MT: adding a special duty roll and bonus skill rolls from high roll results, I also changed how a few of the cascades worked to add in some Mercenary and High Guard skills without using the whole long form generation).
I do have to confess that I did see the worst possible luck on survival rolls that night that I've ever seen. A noble missed a 3+, one player lost every single character he tried to roll up (and these were merchants and marines, not scouts or belters). I also saw a diplomat character go from an initial Intelligence of 2 to a final of 6 by the end of mustering out.
And whoever of you suggested giving characters level-0 in all of the skills from table 2 (Service Skills) is a genius, that really is a useful technique.