Oh, that's a tough one. I feel like the answer is a bit of a 'it depends on the child'. I bought 'Cici' for my niece thinking it looked cute. The illustrations are bright and the main character is a girl, which was a plus. But reading it aloud, I noticed some of the language and the situations are a little more sophisticated than a typical toddler book. It's not a board book with one word per page, you know?
There's a subplot about Cici feeling left out when her best friend makes a new friend. The emotions are handled well, but my four-year-old got really worried and kept asking if Cici was sad forever. It resolved happily, of course, but it sparked a longer, more anxious conversation than I expected from a bedtime story. For an older kid, maybe five or six, it could be a great conversation starter about friendship. For a really young one, it might go over their head or cause unnecessary worry. So I'd say it's more suitable for the kindergarten crowd than the preschool set.