That's quite a big blood for that age but some grow faster then others, as for weight to length ratio it sounds about right to me, I have a 6' female P. Brongersmai that when she's up to weight, prior to breeding is around 20-25lbs, but she is huge and no where near overweight. I have fed my bloods for the first year every week second year every 10-14 days and after that every 14 plus days depending on how the blood does weight wise. This is just what I do, by no means right or wrong, everyone has their methods. I have also herd that if you can't see their spine at all they are overweight. Here's a video that shows my female right before I bred her for the first time.
