Hi @theresacorbett
Have you seen this thread?
It mentions a lot of books that people have read, including some from Cyfres Amdani.
I suggest that you read the descriptions there and on Neil’s Parallel Cymru and then choose the books that appeal to you most. Why not go for both sylfaen and canolradd? I like to have books at various levels of difficulty. If I really enjoy a book but find it difficult then I will tackle it with a dictionary to hand. It’s comforting then to go back to a book that I can read more easily. I don’t know what level I am at, because I have never been to any classes. I have done the SSiW challenges with a bit of Duolingo on the side. Enjoy your reading.
Sue