Hi,
Just a thought. It might be better to find an experienced tester who has tested 5 year olds and let them help you figure out which test is best for your 5 year old. Depending on what strengths and weaknesses you may already know about, some testers can adjust the test to help you discover additional strengths or weaknesses. An experienced tester who isn't rushed will know to give the child a break, offer multiple sessions, know how to engage the child and make it interesting, etc. Challenge/encourage the child to try and guess the answer even if hesitant.
Good luck!