I don't think theres anything wrong with the ribs.
Even as adults we can see the ribs.
Females can lay eggs as early as 6 months old, but through diet and heat control we can control how many they lay, and even prevent them from laying.
Dez has a great vid on egg bins, which you can find at the top of the cham breeding section.
Egg laying is nerve racking, but as long as you provide the right environment for her, she'll do all the work.