Mayan/Chinese calendar wrong?

Elicks
So the Mayan calendar process works by taking the age of conception and the year you conceived. 
​If both numbers are even or both are odd it's supposed to be a girl! 
​If one of the numbers is even and the other is odd it's supposed to be a boy!
​So with my daughter I was 19 when I conceived and the year was 2010. So that would mean my daughter would've been a boy and let me tell you she is ALL girl from the top of her head to the bottom of her feet! Anyone else use the calendar the Mayan or Chinese and it got it wrong?