A computerized adaptive nursing licensure exam selects each new question based on how you've answered so far, rather than delivering a fixed question set to every candidate. That changes how it's reasonable to prepare.
The exam is estimating your ability level, not counting your score
After each answer, the exam re-estimates your ability level and picks the next question to match it. A string of correct answers means the exam is testing whether your ability is higher than it initially estimated, not that you're "doing well" in a simple sense.
Exam length varies by design
Because the exam is trying to reach a confident estimate of ability relative to the passing standard, some candidates finish in fewer questions than others. Neither a short nor long exam by itself indicates a pass or fail.
Why mixed-topic practice matters more here
Since you can't predict which topic comes next, practicing in mixed blocks — rather than one nursing specialty at a time — more closely matches the actual experience of not knowing what's coming.