I have 3 younger girls who all started going to DLR at age 4. First daughter was a daredevil and she loved it. I was the one who wouldn't go on it! By the time she was 5, I worked up the nerve and it has been one of my favorites since.
The year her twin sisters turned 4, we all went to DLR. Older DD was 7 by then. One twin, another daredevil, couldn't wait to go on ToT. Other twin did not want to go on, and surprisingly, big sis was no longer as much of a daredevil then. I think there is a time when the concept of mortality kicks in, LOL. Anyway, she still went on as did little sister, but other little sis chose to sit that one out.
We had no issues with the preshow part. Every kid is different and if they are adamant that they want to go on it, I'd let them! Same in reverse. If there is serious hesitation, then I'd save it for another visit.
My oldest child (a boy, who is now grown up) wouldn't go on ANY scary ride until he was in his late teens. I was afraid he'd never forgive me for talking him into riding Space with me when he was 12. I really did think he'd like it, LOL
