How does "A & P" by John Updike work as a story initiation?

To ascertain whether John Updike's short story, "A
& P," is a initiation story, a definition would be of help. Generally I refer to
the story as a "rite of passage" story, but it is, technically, an initiation story.
Mordecai Marcus, in his article "What is an Initiation Story?" provides us with the
basic history of the initiation story:

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The name and analytic concept of the initiation
story derive basically from anthropology. The most important rites of most primitive
cultures center around the passage from childhood to adolescence to maturity and full
membership in adult society. Anthropologists call these rites
initiation...

The
author then goes on to describe how fiction can reflect the concept of such a ritual, in
terms of literature. Alexandra Pulme cites Marcus' work in the
following:

In
his work about stories of initiation, Marcus offers a provisional working definition
which contains the above mentioned aspects.

An initiation
story may be said to show its young protagonist experiencing a significant change of
knowledge about the world or himself, or a change of character, or of both, and this
change must point or lead him towards an adult world. It may or may not contain some
form of ritual, but it should give some evidence that the change is at least likely to
have permanent effects.

In
essence, then, the definition of an initiation story is one that shows a young character
taking a step or steps that lead him (or her) "toward an adult world," with effects
which will be permanent, life-changing.

In the story "A
& P," Sammy is working in a grocery store. He is an adolescent who reacts as one
would expect a young man to, when three adolescent girls enter the store dressed in
bathing suits—his jaw drops and his eyes glaze over. One of the girls, who he refers to
as "Queenie," has the beauty, poise and self-confidence (in his
eyes) of a queen. However, when the manager criticizes the girls for their attire, the
focus shifts from these secondary characters to the change that Sammy goes through
within an instant.

Updike's young character takes exception
to the manager's comments, though the manager is simply doing his job. Like a knight to
the rescue of a beautiful princess in an Arthurian legend, Sammy defends the young
girls, though they have already left the store. Sammy disagrees with his boss and then
quits his job. His boss, knowing that Sammy is making a mistake to take exception to
such a little thing, tries to reason with Sammy, but the boy has made up his mind. In
the process, Sammy realizes that somehow something within him has changed: he is a
different person than he was when he arrived at work that day. He knows the world has
changed for him.

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...my stomach kind of fell as I felt how hard the
world was going to be to me
hereafter.