I have a '07 girl who is at 2100 grams now, who still needs to put on weight from being bred by her previous owner.
My '08 girl is at 2000 grams who is also underweight since she's been off feed from winter, being bred by her previous owner, then coming down with a RI in transit of me getting her which also made her not want to eat (she doesn't have the RI now).
My biggest girl is 2800 grams and I believe she is roughly ~4-5 years now too, but her hatch year is unknown.
Snakes grow at different speeds, there's many factors that determine how big a snake is at x,y, or z years of age.