How is Peter Cratchit presented and what is his role within A Christmas Carol?

In A Christmas Carol, Peter is the eldest son of Bob Cratchit and makes an appearance in stave 3 of the story. In this stave, he is presented as an energetic and active participant in the Cratchit celebration of Christmas. Peter goes to fetch the goose, for example, and mashes the potatoes with "incredible vigour."
In addition, Peter is presented as being on the cusp of manhood. Bob has just found a "situation" (job) for Peter that will pay him a "bewildering sum" of money each week. Moreover, Peter seems very keen to be a "man of business" and immediately begins thinking about how he will invest his money.
By presenting Peter in this way, we see that his role in the story is to show how poor families must utilize each member to contribute to the running of the household, particularly to the family income. Although he is very young, Peter's future is already mapped out: he must go out to work and contribution to the family's income because their state of poverty requires it.
Through Peter, then, Dickens highlights the burden of poor children who function as physical and economic assets to their families.