Having raised a few of them, many grow quickly and put on lots of size, and other hardly grow at all and seem to take forever to grow up. THere are many variables involved. Hydration, diet, temp, hibernation, or not…
It is so variable hat I don't think there is a "norm" or "average". Hopefully you would see steady monthly growth until the males reach 5-6 inches or female reach 6-7 inches. Once they reach that size, which can be anywhere from 2-10 years, they typically slow way down on their growth.
Thanks Tom! He’s just at 5 inches. His length has changed slowly over the last year. His weight is still increasing, but at small increments per monthly weigh in. Sounds like he is doing fine.