1) Why do so many teenagers owe money? Why are they in debt? If so many teens think they know how
credit works why are so many in trouble with credit?

Lot of teenagers are in debt because they take loans which they often are not able to return because they still haven't acquired skills to be more competitive on the labor market thus they don't earn enough.

Explanation:

There are millions of teenagers that have loans and lot of them end up in trouble because they are not able to return their loans. The reasons for taking loans are mostly based around funding their education or staring a business. Unfortunately this often backfires.

The teenagers end up in a situation here they have a loan and need to pay it out, but they are still very young, inexperienced, and don't have skills to be more competitive on the labor market. In general, during this period of their lives they can work in low payed jobs which are often barely enough to satisfy ones basic needs let alone to pay off a loan in meantime. Not thinking further forward is also a problem and that comes from the young age and inexperience, so the teenagers end up in a situation where they think that their dreams will come true and will have no problems, but it turns out to be the opposite.

there is an explationation of this on a site called crash   course world history 1

the main idea of monster inc is good and evil

if im wrong correct me but have a blessed day!