There's sayings that reptiles continue to grow for their entire life, but I don't know if its true. The older they are they do certainly seem to be bigger.

If its a male, and he's been fed appropriatly sized meals weekly his whole life, I would say he's probably close to his adult size now. (without seeing him in person I really have no idea)

If it's a female, and she has too been fed appropriately size meals weekly, she could likely still grow for a couple more years before she reaches her average adult size. Even then, she could continue to grow to be one of those 3000 gram girls.