I don't know, by a year most of mine would be around the 500g mark so 300g then does sound on the smaller side but I've also had BPs that have been really poor feeders and with a regular diet, they'll bounce back and start growing pretty well. Like, my first BP was probably small for years since I had no idea what I was doing when I first got her and was feeding her about once a month but once I got her on a regular diet, she shot from 700g to 2000g in just a few years.