We too our oldest on it when he was 3 and he LOVED it. Our youngest now will turn right after our trip and though he's tall enough, I really don't think he's remotely ready for it. All depends on the child. My youngest is autistic though and we can't really explain the ride to him in a way he'll understand, do he won't be able to make up his mind about it. If your child wants to go, let her try it.

It's a pretty good "beginner to thrill rides" attraction. One thing I learned on Dinosaur is just because they're tall enough does not mean they are ready. Yikes. That was is rough at twice the age. SM though is tame w/ the exception of the drop, and that's fast and smooth.