You mentioned your DD is saying shr is tired and feels like like she is working too hard... But is she able to tell you more? I recall (and seen) how much emphasis regular K had on skills like writing. I was surprised to see the amount of homework and dependency on those motor skills... Which would have been hard for DS since his motor skills are age appropriate but his capacity to learn new material was above average and the repetiton of same material drove him crazy. His current program does not have that volume and emphasis on writing skills in order to access new material so he is not expected to have same level motor skills of kids who are up to a whole year older than him, but rather, at his pace of physical development while allowing him to grow in other areas at a more rapid pace that keeps him engaged.
So - is the "too hard" being due to too much new material or due to something like constant pressure to be at same motor skill level as kids who are older? To me, those are very different at this age, when their motor skills may not be at the same level as their minds.
I would say see what the testing is... Even if she is gifted, her profile may be very different from her brother. So what works for him won't work for her. It is good that you are asking these questions if you have doubts on her placement... So keep following your gut and see where it goes.
