According to the official Terminator franchise timeline established in "The Terminator" (1984), John Connor was born on February 28, 1985. This date is consistently referenced across licensed materials, including the films, television series, and official novelizations.

Actor Edward Furlong was 13 years old during the principal photography of "Terminator 2: Judgment Day," which took place from October 1990 to March 1991. His youthful appearance was a key factor in his casting, as the character needed to look significantly younger than his actual chronological age within the film's narrative.

This is a common practice in filmmaking. The script required a character who was a young teenager, around 10 years old, to fit the story's needs—a child who is old enough to understand the gravity of his situation but still vulnerable enough to need protection. Casting a 13-year-old actor allowed for a more mature performance while maintaining the necessary visual youthfulness.

No, the film "Terminator 2: Judgment Day" never explicitly states John Connor's age with a line of dialogue like "I am X years old." His age is derived entirely from the established timeline of the franchise, specifically the gap between his birth in early 1985 and the film's setting in 1995.

The primary action of "Terminator 2: Judgment Day" takes place in the year 1995. This is confirmed by multiple sources, including on-screen dates, production notes, and the official timeline. The opening scene shows Sarah Connor's nightmare of the nuclear apocalypse, which is dated August 29, 1997, establishing that the present-day narrative occurs two years prior.

John being 10 years old is central to the film's emotional core. He is at an age where he is forming his moral compass. His interactions with the T-800, a machine learning human values, mirror his own journey from a rebellious, fatherless child into the future leader of humanity. His youth makes him a target for the T-1000 and necessitates the protective mission of the reprogrammed Terminator.