Our gifted school doesn't insist on testing for entry, however I think that they will be far more open to placing her ahead of her age if we have test results to back up our feelings. The level of the other kids, especially in the preschool, probably because not all are tested, is not as gifted as we'd hoped, and we've had trouble convincing them to accelerate my son to be with kids working on his level, even though they are happy for him to work on his own level in the classroom with his age-peers.
Unfortunately she turns 4 a week after school begins, which will be rather late to convince the school of placement issues. Certainly it made it harder when advocating for my son, it was so much easier to leave him where he was while deciding what to do.