Answer 

There are different considerations for working at amazon on age bases. 

With this chart, it is clear that a big number of employees is between 25 and 34 years old and the least number of employees is between 19 and 28 years old. 

Conclusion 

Do you get the same payment as people who are older than 21 years old when you are only 18 years old?

Does amazon allow shift working?