I have seen babies born in July that were 200g now, my girl hatched July 10th and she is 387g empty taking small rats every 5 days (50-60g).
Every snake grows differently, so you can't really estimate well off of other peoples snakes. That being said, fresh born hatchlings can usually take hopper mice without issue. So she might be growing slower based on the 7day/small prey diet.
I'm sure she will start growing like a weed once you get her on the bigger prey :) welcome and Congrats on your baby!