My son first rode ToT when he was 3 1/2. He liked it, although he was a little scared. The next few trips he enjoyed it, then two years ago when he was 5YO he was scared to death and told me afterwards that when he grew up and had kids they would have to ride by themselves because he was never riding again! Since then he still rides, but I still cannot figure out what scared him so badly. My 4YO daughter rode for the first time this year, and pronounced it "only a little scary". Take them throught the queue and let them decide for themselves. My bet is your 5YO will be OK.