I was able to get this resolved by contacting Apple Support and also figuring out a workaround on my own.
As stated before, my daughter's age was showing up as 2 when she is 19. I contacted Apple Support and after explaining the issue, they had my daughter change her birthdate by going to appleid.apple.com. But she got an error trying to change it. I remember seeing somewhere that if a child is under the age of 13, the age can't be changed without getting support involved. So I had my daughter change her birthdate to be 13 minus 1 day. Since we did it on Dec 23rd, 2019, she changed her birthdate to be Dec 24th, 2006 (e.g, 13 years minus 1 day). The change took successfully.
Then the next day, when she turned "13", she was then able to change to her correct birthdate. So it was a two step process to actually get it done.