Welcome to the wonderful world of Borneos. In all my experience, they have to be the most tempermental snakes I have dealt with. One minute they can be finem and seriously 5 minutes later they will want to bite your face off. That doesn't mean that they are overly aggressive though. The hissing or huffing is completely normal. Borneos and Bloods are both extremely vocal snakes. Before you go picking her up or touching her, make sure she knows you are there. I usually bump the snakes enclosure, or knock on the glass so they know that I am not something attacking them and they doesn't have to defend themselves. Just wait until she gets some size to her, they love to throw their weight and strength around. She will start to bump you with her body when she doesn't want to be touched. My largest Borneo is 5'11" and right now about 14 lbs, when she bumps my hands against the side of the enclosure, I usually come out with bruised knuckles LOL You need to get to know what your Borneos signs are so you know when and when not to disturb them. It's a long learning curve with these guys and you will get bit. Let's hope it's not when she is an adult though
PS. When moving my snakes into new enclosures, I usually don't handle them for atleast 48 hours. Borneos and Bloods stress out waaay to easily and that is why they are so defensive. You've probably noticed when your girl gets worked up, she breathes really heavily almost hyperventilating, but it's normal. Just leave them be and they will settle down.
Hope this helps a little