This is the first book in the B Series to use both sentences and a name.
Hence, it is the first book to use capital letters. These letters are 'I' and 'J'. The sentences all begin with the phrase 'I am ...'. The texts on pages 7 and 8 begin with the name 'Jelly' and, hence, use capital letters.
The texts on each of these pages are strictly not sentences, because no verbs are used.
However, full stops have been included to help teachers of 5 year old children with the rule of 'using capital letters and full stops' consistently.
Similarly, the capital letter form of 'The' has been used on page 5 to be consistent.
The letter 'y' has 3 phoneme/grapheme correspondences and only one is used in this book.
It is best, at this stage, to teach the word 'Jelly' as a word to be learnt by sight.