It should be age normed.
Here's a percentile chart
http://www.iqcomparisonsite.com/iqtable.aspx
Use the 15 SD Percentile column. I don't think the scores are as rare as the chart indicates, but those scores are still pretty rare. The "age equivalent" scores are probably a couple to several years older, though this doesn't necessarily indicate possession of higher grade knowledge.

I'm sure your kid could handle maybe 2 or 3 years acceleration. Ideally you want a way of moving quickly through the material to avoid gaps.