greenlotus - I have this feeling your DD will do very, very well on the testing. She probably cannot judge how she is doing on the test because she is likely having the experience of not IMMEDIATELY KNOWING EVERYTHING. That is normal for a high-achieving kiddo on an out-of-level test.
DD (3rd grader at the time) walked out of the EXPLORE clearly not as confident as she usually seems after testing. Her reaction to the test had NOTHING to do with how well she actually did - so don't drive yourself nuts and read too much into her sense of how testing is going.
Best wishes being sent your way...
