The guy I rescued my female BP from, said she was 3 years old. She is 3.5 feet long and she is 1187grams (we've had her 3 weeks.)
I found her breeder and she said that because the other owner underfed her, (once a month, ) She's not as "girthy" as she should be, and looks more like a 1.5 year old, even though she's 3.
So, it's really hard to tell age.