All I can offer is my own experience. I got my BP around April, and he was a mid/late 08 born. When I got him he was around 230g, and now he's weighing in at 499g (as of 2 days ago post deficating). I might say he/she is a bit small, but if they are eating consistently I would say you should be fine, all depends on the animal. If they are eating consistently and the appropriate size animal I'd say they are probably okay.