Welcome to TB!
Well, surprise, I think Casper is a little girl!
Since she's not yet in condition, her cere will be whitish-blue until then, so don't worry. From that photo, it doesn't look like anything's wrong with her, but if you post a photo in natural light of her cere, we will be able to tell you better the gender as well as any possible problems there may be!
Your two birds are gorgeous, I hope to see more pictures of them soon and feel free to ask us anything!