Is it a male or female?

I bought a lutino/whiteface (albino) at a bird show last week and she thought it was a male but she pelvic bone sexed it and said that the pelvic bones were fairly close together and I went to sex it and they seemed fairly far apart!! Does the pelvic bone test work Or do you have to go by behavors? Cause I am thinking its a female cause it whistles but not a whole lot!! I was hoping to breed it to my female (cinnamon lutino whiteface) and get baby albinos next year!! But if it turns out to be female I will trade it at the show in april!! It's only 5-6 months old so can it start whistling more later? I would like to know!! Thanks Melissa & the flock