I think you should work up to it with perhaps Goofy's coaster, maybe Big Thunder then this one. You can explain that it goes backward, is partly in the dark but you won't know until you do it unfortunately. It helps that a lot of it is visible from the line. I will add that we had my daughter go on Splash Mountain when she was really thinking she didn't want to. It is another ride where you can SEE the big drop and it scared her. After that, she rode everything including Tower of Terror and loved it. She was 4.