yea, he/she is an adult.
the whole "big thing" is relative to being wild caught and exposed to alot of heat, food, and oxygen (not 100% sure)
i have a female that when the tail is extended, 7-8 inches from claws to tail.
and i have a male whose 4-5 in the same way
they are both adults.
so yeah. i didnt know this until a few weeks back too