Weight can vary greatly from one individual to another, depends on several factors, weight when hatched (some hatch at 45 grams some hatch a 90 grams) how fast they get started (some will start 2 weeks after shed some may start 6 to 8 weeks after shed), prey size (obviously the one starting at 45 grams will have smaller preys than those starting at 90 grams) feeding frequency, fast, genetics etc.
Over the years I have seen animals in all ranges from animal that are 1000 grams at a year to some that are barely that by age 5, so while it would be under the average, there is more to it to the picture than the weight itself and the most important is the overall look and body proportions which in that case look good to me.