If you're taking it next week, for the most part you're as prepared as you're going to get.You might be able to learn a thing or two or polish up some knowledge, but if you haven't been preparing for it all along then you probably aren't going to be ready for it.
I've never taken that test specifically, but a quick google reveals its a college entrance exam for nursing programs. I would imagine the expectations is proficiency in high school senior level math, science, and English. So as far as difficulty, if you can do high school work it should be no problem. If you can't, it will likely be a challenge, perhaps an impossible challenge without further prep.
That's not an indictment of you personally. I barely graduated high school due to profound laziness and inattention. I never took proper college prep math courses(algebra, geometry etc). I took accounting for my math credits. If I had to take that test tomorrow I'd bomb it.
All that being said, both of my parents went to college, for nursing no less, in their middle/late thirties. It can be done and is done all the time. There seems to be plenty of review material for that test specifically. Get after it and you'll do fine.
