Just to ease your mind a little, I've bought hatchlings, yearlings, adults and with proper care, they all settle down with time. That's the great thing about BP's and even if they're a bit nippy and defensive, their bites are comparable to a mosquito bite so don't worry about getting tagged a few times. Generally, younger balls are defensive and when they haven't been handled much or they've recently been re-homed, they're even more defensive. You're a threat right now and anyone or anything that goes near your snakes cage is a threat. I have a yearling pied who is finally starting to settle to the point that he doesn't strike at the tub when I walk by and I also have a little YB who strikes endlessly the second I open the tub to clean. I've had balls that literally came out of the egg tame as could be. They're all different and they all calm down in their own time but the best way to judge how well your BP is doing is by their feeding habits. If your ball is feeding then you have nothing to worry about. That's a great sign. The first thing to suffer when a BP is severely stressed or in an inadequate habitat is their appetite. So I think you made a good decision - your snake seems to be adjusting well.

My rule of thumb is 3 consecutive feedings before I start to handle. Everyone's different and there's no golden rule but that works for me.

Good luck.