Many people will probably say that their weight really varies depending on the snake. I personally have a normal that's 1301grams and is only 1 year 8 months old, but he's a porker, lol.
I found a few charts that average the weight of 10+ BP's and i'd say if your BP is 1022g at approximatly 24months of age, the snake is doing well size wise.
This chart might help a bit, but again it's an average and all BP's grow differently. It's based off 15 BP's weight data so it's a pretty decent indicator. You can even check the individual snakes data and really see how different their weights can be. http://www.thereddragonsden.com/avgweight.htm
(I take no credit for the chart or the site, I found it when doing a search of BP.net!)
Hope this helps! Good luck with your new BP!