Sally Field was about 18 years old when she started playing Gidget in the TV series Gidget , which premiered in September 1965.

How the age is calculated

Sally Field was born on November 6, 1946.

The TV show Gidget first aired in late summer/early fall of 1965 (September 1965).

If we count from her birthdate:

  • As of September 1, 1965, she was still 18 (she turned 19 in November 1965).
  • So, during the first season of Gidget (1965–1966), she was 18 going on 19 years old.

A bit of backstory

Gidget was Sally Field’s first major TV role, launching her career as a young actress.

She had actually just graduated from high school a year or two earlier, so she was very close in age to the teenage character she played.

So, in short:
Sally Field was 18 years old when she began playing Gidget in 1965.