Your Cookie is 100% male and his cere will go through some changes as he continues to grow till he reaches maturity.
You will notice the cere gradually getting a deeper purplish colour and when he is about to turn 6 months old, his cere will change to a royal blue colour.
Depending on his genes, he may keep the immature purplish colour on his cere, but since he is a single factor dominant pied budgie, his cere will most likely mature into the royal blue colour.
RIP sweet Tito (Summer 2008 - January 17th 2013).
You are missed and never will be forgotten.