They grow very quickly at that size when they're fed regularly.
Just as an example, here's a few of mine and their recorded weights after two or three months. Fed every 5 days most of the time (but not always).
2013-08-22 : 83
2013-10-21 : 230
2013-09-15 : 142
2013-11-16 : 287
2013-08-16 : 97
2013-11-17 : 295
You'll probably get about the same growth.