Have you ever noticed how much our dogs observe us and know what we're going to do, before we THINK we've given them any cues? They know we're going
to leave for work, or to go to the store, or maybe walk them, or take a trip, because they have little else going on other than paying attention to all our moves.

Snakes are sorta like that too: only they aren't distracted by sounds (voices etc.) or much by vision; their instincts direct them to lay in wait for prey, so the moment
you approach & open their cage, they snap to attention ready for battle with incoming rodents. They cannot identify YOU by sight, and you are too far away for
scent (at least the way you've been approaching)...since they are thinking of nothing but "here comes dinner" they easily assume that you're "it" when you approach.
Don't take it personal...it's only an honest mistake on your snake's part...and because she is now conditioned to expect live prey that she MUST subdue quickly.
They use vision but it's only about "motion" (prey???), not a means of identifying. To survive, a snake usually must "bite first & ask questions later".

Another thought: when you train a dog, or a human, "sporadic reinforcement" (not getting the treat EVERY time) actually makes the subject work harder for it.
I can't say for sure whether the same is true for snakes but judging from yours...sometimes it's a mouse, sometimes it's you, but each time she's trying harder, yes?

Anyway...communicate what's coming her way with scent and touch, & if you need help switching her from live (it takes patience but there's tricks to it) we're
glad to help you. Look at it this way, she's only a couple years old and she could live to be 30-40 years with good genes & good luck. Wouldn't it be nicer for
everyone (her too) if she calmed down & learned to be a good pet again?