Which vietnam policy came first in the johnson administration?
gulf of tonkin resolution
tet offensive
operation rolling thunder
vietnamization

Correct  Gulf of Tonkin Resolution

Dates of the items listed:

Further detail on Gulf of Tonkin Resolution:

The Gulf of Tonkin Resolution, passed by Congress in August, 1964, after alleged attacks on two US naval ships in the Gulf of Tonkin.  The key wording in the resolution said:

That resolution served as a blank check for President Johnson to send troops to whatever extent he deemed necessary in pursuance of the war.  Between 1964 and the end of Johnson's presidency in 1969, US troop levels in Vietnam increased from around 20,000 to over 500,000.

answer: 25.8 years old or 25 years old