Is my new Budgie female or male?

[Alfie]

I bought a budgie two days ago at a pet store. It looks like she/he's been through the first molt, so is the cere color final? In most females, I've read it becomes brown and crusty, but any color besides a dark blue or purplish means it's female, so, just to be sure, this budgie is a female, right?
http://s1322.photobucket.com/user/lblabla75/library/?view=recent&page=1

[Pajarita]

It looks like a hen 4 to 6 months old (didn't the owner of the petstore have the paperwork of when she came in?) but it's difficult to tell without wings and tail and from just one picture. Hens ceres don't turn brown and crusty until they are in breeding condition.

[Alfie]

It turns out the pet store owner did almost nothing correctly. He literally just chopped up her wings, took the money, boxed her up, and gave her to us with the receipt. But thanks for your response, I was wondering because I saw someone who had a budgie which began with a cere just like mine has but is now becoming a purplish shade... I guess it's just her budgie maturing.

[Pajarita]

No, purple cere means a boy, not a girl. When girl budgies become adults, their cere turns pink or beige (flesh colored) and, when they go into breeding condition, it turns brown and gets crusty but it goes back to pink or beige in the resting season (winter).

[Alfie]

Ok. Why does it become crusty? Is it because it is simply unneeded in females for mating or something?