I don't see why this is a "surprising result". However, I've read elsewhere that all children have difficulty separating fact from fantasy prior to about age 10, give or take, and this is a study of 5 and 6 year olds. So it begs a number of questions such as whether there might be a boomerang effect later in life for children from religious families, etc.

All in all a piece of fluff that doesn't mean much, from a source that doesn't sound particularly credible. Although they are just quoting Huffinton Post:

[huffingtonpost.com]

... who in turn appear to be referring to this:

[medicaldaily.com]

So at least they provide links to check it out.

Is "themindunleashed.com" a reliable source of information?

Not surprising.