Birthday calculation is like this:
Algorithm: According to the setting, the story background is 1840s.
Anna sings for the first time in Forever. Anna eats solid chocolate, which was invented after 1847, so the story takes place in 1848 or 1849.
There is a line behind "Seven In the snow", which indicates that the Queen was crowned in July.
Later, a full moon appeared in Love is an Open Door. According to the calendar year, it can only be the date1848 July 15 or1849 July 4.
Finally, according to the designated group or movie, the queen was crowned at the age of 2 1 year, so the queen's birthday was1July 827 15 or1July 4, 828. There are no more detailed details in the movie.