Even the vet will not be able to give you an exact age, once a budgie is fully mature it is not possible to determine the exact age. The iris rings are fully visible in him so all that you can really say is that he is at least a year old. Can you post a full frontal picture of his face?Unfortunately I don't know! The shop owner said he was 12-14 weeks but it's very clear he's much older than that. He's at least a year old, but I'm not sure how else to tell without taking him to the vet.