This book is about how raina can't wait to be a big sister but once amara is born, things aren't quite how she expected them to be, amara is cute but she's also a cranky, grouchy baby, and mostly prefers to play by herself.
This isn't something that can be anwsered with a simple number. Cynicism about annything is more a part of personality than anything else. It is beleived to develop as people age, and cynicism about a particular thing would probably begin as they start to lose something. If we base beauty as looking youthful then we could say late twenties to early thirties (so around 28-35) as that's when signs of aging begin to show.
Know you audience and tailor your writing to them. This will help them relate or "see" what you're writing.
If you are telling a story to young children, use simple words and be descriptive and enthusiastic.
If you are writing to impress a college admitter, use complex words and formal diction.
If you are writing for a religious audience, maybe write a sermon0type passage and include religion in your writing.
It is a special kind of name such as answer A Creon, son of Menoceus