cockatiel matureing

Question
i have a cockatiel that is just about 2 years old and have been told by the local pet store that it is reaching sexual maturety. my cockatiel has recently been acting very strange and has been lifting up its tail and making squeaking and chattering noises. how can i tell if its a boy or girl? and also we recently bought a cockatiel nesting box and it is scared of it. is that normal? will it ever use it? and one more thing, how would i know if it is about to lay an egg? what are the first signs?  

Answer
Sam,

Depending on the color mutation you have the males normally have a much brighter and cleaner orange spot on the cheek area. Also females have bars under the tail feather where the tail and body meet. From the description you gave me with the lifting of the tail feather it sounds like you have a mature female wanting to breed.

Wayne