Even though the homemaker is employed as a family unit, they are not part of the recognized work force, per se, and therefor are not part of the database of unemployed.
An unemployed person can be a person who has no job and is trying to find employment. Unemployed can also be used to describe a person who is physically capable of working but is too unmotivated to...
In the US it is 18. It is then that you become able to own property, sign contracts, and have all of the responsibilities of an adult (except with regards to alcohol, until you turn 21).