Boy & Girl??

Pretty sure my blue Budgie Kevin is a boy as cere is very blue…. Both are very young… Nellie who I initially thought was a little hen but now I’m thinking male? Her cere is purplish  She/he is a little younger than Kev… they get along extremely well and taming so far has been pretty smooth considering  (both from a very small over crowded cage at a pet shop with very little human contact ) second photo is first thing of a morning they were all fluffed up after a long preening session…