I personally would be extremely hesitant to recommend that someone take AoPS pre-algebra based only on the ability to pass that screening test.
Really, it's the full year of math in 3 weeks that worries me. If you're covering a chapter a day (which, according to the syllabus and the textbook, they are), there's no time to get up to speed.
I've emailed CTD to see if they can tell me more about the expected level of preparation. Their Algebra I requires a 22 on the EXPLORE (90th percentile for 6th grade talent search kids), whereas pre-algebra requires basically "is good at grade-level math." My DD would be at the "is good at grade-level math" end of that spectrum (50th percentile for her grade on the Math EXPLORE).
