1. Large in physical or mental maturity. Can refer to teenaged girls that are Jailbait, or boys that are Early-Bloomers, although, sexually maturity doesn't necessarily mean that said person is Big. They must also act more intelligent, mature, and responsible than their own "age-mates"
They also tend to be of high statute and are very popular
Also can be very mature teenagers that handle their own finances and assets while they are still under 18 (buying cars, selling things on ebay, making profits, etc..)
Such individuals have a large amount of trust from their own parents which in turn allows them to obtain a large amount of respect from their friends and everyone that they meet.
These are also people that are so-called "Boss"
"Yo, Jim is a Senior now, but he's bought and sold 10 different cars since he was a sophmore. Dat nigga is Big!"
"Oh my God, Sarah is only 12? I thought she was about to be 16..... She is so Big."
"Hey Mike, that's a sweet ass DC2 you got there, what happened to the civic?"
-"Well, I sold it to a guy at one of the city car meets."
"Wow, man. You sold your car and your in 11th grade? Your really Big man!
-"...Oh..?... thanks?... I guess....."