Ball getting angry.(Never been bit newb)

So I've fed my snake 3 times since I've owned it, and what I now presume is a she because of how large she is an how fast she is growing. But she has become a lil cage aggressive and have not been able to hold her since the first feeding. I would really like to get her out to replace substrate to keep the humidity levels up because her last shed is still half stuck on her an would like to give a nice soak for it to come off. About a week ago I blacked out her 40 gallon tank on 3 sides an half way on the front because she backs up when you look at her. I dunno what to do. An estimated guess on her size would be about 16-18 inches long.

We'll need general husbandry information: hotside/cool side temps, humidity, hides?, light/heat sources, etc.

Sounds like it's more than likely a husbandry issue. BPs don't tend to become defensive unless something's wrong with their environment. She may not feel secure in a 40g if she's that small, provide her with lots of cover, balled-up newspaper does wonders.

That's a big tank for a snake that size. She's probably just scared of you and sounds like she needs more humidity. X2 on lots of crumpled up newspaper. I'd add some damp moss. If you have a screen lid, cover half of it. Do you have a heat lamp or uth? Do you have a thermostat? What else is in the enclosure? A full description of your set up will help us determine the best advice.

Starting from the left to the right side of the tank. Back left, cold hide. Front left, large water dish. Middle of tank a wood structure with leaves. Front right has an under tank heater. Back right is its wood hide that she never comes out of with a heat lamp right above it. I have an accurate thermometer/hygrometer with the probe in the hotspot. Hotspot is measuring 90/cold 82. with 38% humidity. She has eaten ever single time an never regurgitated.

I'd bump up the humidity with some damp moss. I agree with the cluttering up as well. If you don't like the look of crumpled newspaper, fake vines do wonders and also maintain that 'natural' look. And they're only $1 at the dollar store :) I have a snippy one and she's definitely calmed down with a cluttered tank.

Also, she's probably feeding off of your nervous vibes. If you hesitate or make quick, jerky movements, that will put her on edge. I'm a little ashamed to admit it, but I was once a bit afraid of my teeny tiny little girl lol. Be confident, move calmly and you should be good to go. And if she bites, then you get to join the Bite Club! I'm a card carrying member :) Seriously though, if your concerned about getting bitten, you can wear gloves and long sleeves. It's a little overkill IMO, but it will protect you pretty well, and as a bonus should boost your confidence as well.

X2 on confidence during handling-- and honestly, a BP bite feels like getting your finger stuck in a rather angry zipper. They let go once they realize you aren't food. :)