-You had better discuss it with your lawyer.
Where can I find the explanations about age freeze? "The denial letter says "your age is frozen on the date that the visa becomes available not your Priority date".
When we filed I485 in Jan 10 2014,our Eb3 priority date is current but the Eb3 Visa was not available to us as my EB3 I140 hadn't been approved yet. Does that mean my daughter's age was not frozen?
-" visa becomes available" = "the priority date is current". When you and your child filed I-485 based on EB-3 when the priority date was current (visa number was available at that time), your child's CSPA age was frozen at that time no matter whether the visa number became unavailable again later (the priority date became not current again).