My supposedly female parakeets cere turned blue!

by Gabrielle
(Monroe wa)

We have a "female" parakeet that we've had for a little over a year. Her cere has been slightly crusted brown for that time up until now, and she is over three years old but we don't know her real age. I noticed a few days ago that her cere was cracking slightly and now it's coming off and the cere is blue! Does that mean she is really a male?