Tiki

We just got 2 new budgies we are thinking the blue one is a female and that the green one might be a male?? I'm a new owner and I'm having a hard time figuring out their genders.The one we think is female (Blue) has a light brown and dark brown cere we think she is about 8 months old to a yearThe one we think is a Male (Green & yellow) has a pink cere with white rings around the nose which is why we are a bit unsure if he is actually a he