I listened to it as an audiobook and it was so nice to follow along the unusual friendship of the 17 year-old Lenni and the 83 year-old Margot. 
It's a wonderful story about friendship, love, a life well lived and death. The audiobook gave Lenni & Margot so much character it was very relaxing listening to the two readers. 
That story showed that there is no age limit for true friendship. Every character felt so special and made this book a perfect comfort read for me.