Hi there, Cheryl!
As you pointed out, the
official Disney Parks Web site lists the height requirement for Kali Rover Rapids at 38". That's the most accurate point of information, of course; while many fan sites exist that provide a wealth of incredible information, your most trustworthy source would have to be anything that comes directly from Disney itself
The confusion might be in that children who are on the lower end of the height requirement - say, 38" - 42" - will receive a wristband to identify them as needing to ride in the specially-scaled child seats provided. These seats have adjusted safety mechanisms that are specifically engineered to ensure the well-being of the shorter rider.
To be sure, you might want to print out a copy of the page from the site. This way, of any questions arise on the day you visit
Disney's Animal Kingdom, you cam pull out your paper and indicate that you have it right from the mouse's mouth!
Have a wonderful trip!
See you later, celebrator,
-Deborah B.