Hi Jennifer,
It sounds like you have a dare devil like one of my little girls! The minimum height requirement for
Expedition Everest is 44 inches, so hopefully your daughter is that tall. My daughter loves roller coasters too and she impatiently waited to be tall enough to ride Expedition Everest. Each year she would measure herself against the height stick. I'll never forget when she was finally tall enough...she ended up riding it 3 times in a row!! It just so happens that she had just turned 6 years old at that time!
Expedition Everest does not do loops, although it does go backwards for a brief period of time. In my opinion, it is no way near as intense as Rock 'n Rollercoaster. I would compare it to Big Thunder Mountain Railroad, but with several bigger hills. If she doesn't have fear, and really wants to ride...I say, "Go for it"! You may even find that she likes it so much that she'll insist on riding it several times. Of course, I let my kids ride Tower of Terror at 4 years old (and they loved it)...so keep that in mind when weighing my opinion ;).
Seriously though, if she wants to ride it, just be sure that she knows it goes backwards for a tiny bit, sit next to her and "Let the Memories Begin"!
Kaylene