After reading until the 11th chapter

In the 6th chapter I had problems to understand why the author changed the tense. While reading I thought the scene was switched 9 months into the future. In the first place as the next chapter started I noticed that Sam had dreamed.

Fascinating is how Sam and Alicia deal with the pregnancy especially because I don`t know youths in my country, who are pregnant.

I´m confused about Sam as he did a runner to Hastings because I thought he isn`t so afraid compared with the future.