Note that if it comes down to AB540 status (i.e. 3 years attendance at and graduation from a California high school), it is not technically California residency. However, non-residents with AB540 status are eligible for in-state tuition and state financial aid, unlike other non-residents.
http://www.ab540.com/Paying-for-College.html (includes a lot of references to DREAMer/DACA people who may be eligible, but you can ignore the DREAMer/DACA-specific stuff if she has US citizenship or permanent residency)
However, if the residency classification is done only at initial entrance while you are still California residents, then it may not need to come down to AB540 status, unless she transfers to a different school (e.g. the common transfer paths CC->UC or CC->CSU) after you leave California.