She hasn't eat from two months and lost a bit of weight

So my ball python hasn't eaten since February 28 and on March 15 I weighed her and she was 852 grams. Just now I weighed her, and she was 831 grams? Could this cause concern or is 20 grams not a lot? I have her out and she is almost as active as she normal is. Temperatures and humidity in the cage are all pretty good and she always has hides and water etc.

Edit: The title is wrong haha. Excuse that please.

0.1 Super pastel

20 grams is next to nothing for an 850 gram animal. It could simply be a big poop that's the difference at this point. Typically 10% is a good ballpark for looking into matters. As long as everything else is fine, then there's no cause for concern.

My girl just ate her first rat last week in about 5 months(Oct or Nov '15). I have no idea how much weight she lost as I don't really pay much attention to it. She would come out at night, thermo regulate and overall looked fine so I figured, she will eat when she eats. I just offered her a rat every 2 weeks when I fed the boas. You can drive yourself mad worrying about BPs. As long as your snake looks ok, husbandry is good, and overall everything seems right, just offer him food every week or 2. You don't want to offer food too often as that can stress them out.

Yeah that little bit of weight could have simply been a poop. My 1380 gram ball can lose as much as 40 grams after he takes a dump. I think 20% of body weight is closer to when you should start to worry, 10% of body weight is barely even noticeable. My ball python lost 13% of his weight, and although he looked slimmer it wasn't an extreme weight loss. Just keep offering once every 1-3 weeks, doesn't have to be on the dot every 7 days, and giving more time in between offers may encourage her to eat.