i have a budgies whose cere is little brown with light blue color is she female i'm thinking it's female because female have light blue cere when not in breeding condition and brown when in breeding condition

Yes she is female

yipeee now my blue pair will breed after 3 months

yipeee now my blue pair will breed after 3 months

Not necessarily. First they have to be the right age. Secondly they have to be in condition.

okay

I think shes a girl