hi! i'm relatively new to this forum although i've lurked around it for at least a year or two.

i'm not sure exactly how to phrase what i'm looking for, but i guess just general advice and to make sure i'm doing everything correctly? i got my first BP in September, given to me by a friend's sister who admitted she hadn't been caring for her properly and knew how much i loved snakes.

the BP in question is 10 years old, is 3.75 feet long and weighs only 1321 grams (weighed in October), and female. apparently, she'd only been fed 2 live large mice every 1 - 2 weeks for these past 10 years.

i was told they'd tried to giver her F/T but she wouldn't take it, yet i got her to switch in one attempt. right now i've gotten her up to small F/T rats and plan on getting her to medium ones.
i guess you could say i'm worried about her weight? 1300 grams seems really small for a BP that's almost 4ft long and is as old as she is. now i've had experience with BPs and snakes before, but since this is the first one i've actually owned i just want to make sure i get it right.

her feeding response is crazy fantastic for a BP, she hasn't missed a single meal or refused any food type. given her age, though, can i expect her to put on much more weight or am i worried for nothing to begin with?