You didn't mention how long you've had this snake? I'm guessing she's fairly new to you?
Snakes are typically shy: the only thing that picks them up in the wild is normally a predator that's about to have them for dinner, so being handled is scary at first.
That said, they usually do learn, with patient & gentle handling, to relax when we handle them; most appear to learn & retain the notion that they feel safe with us.
All snakes have their own personalities too, & learn at different rates. When she balls up, that roughly translates to "go away, giant!" The activity can either mean a
snake is stressed & trying to get away from you, or just that it wants to explore once they realize there's no more cage holding them in. Subject to interpretation...for
some snakes it might also mean they're too warm (easy to forget that we're 98.6*) but that shouldn't be an issue for your BP.
Your snake has a good appetite & eats regularly: a snake that feels stressed may refuse to eat, so that tells me that your snake isn't all that stressed by your handling.
Sometimes the response you get when handling a snake is the result of how you're doing it: snakes like to feel safe, & being out in the open does NOT feel safe to them,
as instinctively they know they're at risk from predators. Instead of holding a snake on your hand/arm, try cuddling them close to your body...they feel safer that way.
You might also want to sit down & relax when you hold a snake...15-30 minutes barely gives them time to get over the shock of being hoisted out of their safety zone.
I've also noticed that many snakes get mellow if I sit in a hammock or rocking chair with them...no idea why, but it seems to work. If you have neither, just sway a bit.
Handling snakes is a conversation, but instead of words, you're using touch. It's how snakes know if we're a predator or a pal.