Jame,
Poor prose on my part.
I should have written "I'd like to strongly suggest that an early start option be included too" because it was my intent to "ditto" your post.
Regards,
Bill
Perhaps it can be somewhat organic?
I.E. assume starting career age is X, and that some sort of pre-career education can postpone it. Or, more interestingly, attach formal-educational pre-requisites (1-year, 2-year, 4-year, 6-year...) for certain careers, thereby forcing their careers to begin more like typical Traveller careers, while others ("Barbarian") begin with no required formal education. I say "required" because e.g. it's possible for someone to have a term of education, only to have circumstances thrust said person into the role of a Barbarian, even though it's probably not typical.