I got a 4. Pretty terrible result for somebody as young as I am, but I suppose myopia and the the spectral aberration caused by eyeglasses makes it harder to distinguish colors.
Huh. So most of them were distinguishable to you? Interesting.
I could tell a properly-placed color apart from the colors two or three spaces away from it, but not usually from its immediate neighbors. My main strategy was to assume that, if a color looked identical to each of its neighbors, it was in the right place. I got a 16, which seems decent enough.
A part of it is the fact this is on a computer monitor though. If you only got a few wrong, it's probably not a big deal.