Why was the author surprised to see Nicola and Jacopo working as shoeshine boys

Why was the author surprised to see Nicola and Jacopo working as shoeshine boys? 

Answer: During his first meeting with Nicola and Jacopo, the boys were selling fruits. Next time, they were polishing shoes to earn money. 

So,it was a surprise for him to see that at this tender age, they were ready to do any type of work.