A 90's kid is someone who was a kid in the 90's. To determine what a 90's kid is, we have to define "90's" and "kid".
90's - Personally, I consider the 90's period to have been about late 1991 to 2001; if I had to put dates on it, it's
July 1, 1991 (the midpoint of 1991) to
September 10, 2001 (due to the tragic and massively changing events of the next day), however years as early as 1989 and as late as 2003 can be considered to have 90's influence.
Kid - Not a toddler or a teen; personally, I'd consider a kid age 4 - 12, inclusive, however the "kid" period could start as early as 2 or as late as 14 for some people.
What I would consider a 90's kid would be someone who spent a majority of their kid years in the 90's; ergo, born January 1, 1983 -
March 10, 1993. The "perfectly 90's" kid, who spent the entirety of their kid years in the 90's would be born July 1, 1987 -
September 11, 1988. However, due to personal experience, someone born outside this range could still be a 90's kid, and someone born inside this range could be an 80's or
00's kid. So if you're born in, say, 1981 or 1994 (or any time between the late 1970s and late 1990s) and consider yourself a 90's kid,
have at it. There's also hybrids of two decades and all kinds of other stuff, it's not a
hard line.
Example:
Person A was born July 17, 1988, obviously a 90's kid.
Person B was born
June 4, 1983, they're a 90's kid.
Person C was born December 25, 1992, they're a 90's kid.
Person D was born January 26, 1984, but they consider themselves an
80's kid, they're an 80's kid.
Person E was born
August 31, 1992, but they consider themselves a
00's kid, they're an 00's kid.
Person F was born May 2, 1981, but they consider themselves a 90's kid, they're a 90's kid.
Person G was born February 19, 1995, but they consider themselves a 90's kid, they're a 90's kid.
Person H was born December 6, 1973, they're too old to be remotely a 90's kid.
Person I was born
March 19, 2002, they're too young to be remotely a 90's kid.