Sure you know...sense you work near where I live.
She is in ATA. Our daughter Kirstin - 1st degree- Level two recommended (name added to the black belt). Mine and yours - kids are right in the same rank or close. She started on her 5th birthday. She just turned 8.
Just for fun... a year + ago I told her she could not drop me. She said she could. I laughed and told her save it until your older. I figured by 16 she ought to be real down with it. So as I am laughing my wife says to me..."Dear, your wrong. I said there is just no way. I turned to Kirstin and said try all you want but I can just grab you and forget it. Without any hesitation she kicked me in the nuts and DROPPED ME. I am a 6-1, 245 lb construction worker. It actually made me puke.
So can your kids protect themselves at a young age? Let me put it this way...they teach the element of strike surprise for a reason.
ATA - I don't think the ATA ever has any tournys against ITA except for really big events. I have a nephew in ATA who is the same level black belt as your daughter who lives in Anaheim Hills. A lot more sword work in ATA. The colored belts a little different in ATA too.
My son also started on his 5th birthday. They test every two months and he tested every time and only had to re-test one time when he failed to break his boards. Took a little over a year and a half to get to probationary black belt. Once they become black belt, they can only test every 4 months...so the climb thru black belt ranks is slower than the colored belts. My 6 year old is a little guy and a crack up to watch....he gets kicked in the face quite a bit which is slowly teaching him to keep his guard up. The owners of the studio like him a lot and have given him more attention because he has been so into it.
My 6 year old, while I never have personally experienced it , can deliver a kick to balls very quickly - with enough power to make an attacker lose focus for atleast a moment or two. The kids have the element of suprise on their hands because adults don't expect kids to fight back, atleast in a way that would actually hurt...And they are very quick.