In The Red Badge of Courage, what were Henry's reasons for becoming a soldier?

It is key to note the youthful and naive enthusiasm
displayed by Henry in Chapter One as he is enraptured by his Homeric ideas of war,
heroism and battle. We are introduced to a very vain, narcissistic and innocent boy
indeed, who, over the course of the novel, matures greatly as he faces and has to
confront both the realities of war and the reality of his own successes and failures.
Note the way the narrator talks to us about this youthful Henry and his desire to
enlist:

He
had burned several times to enlist. Tales of great movements shook the land. They might
not be distinctly Homeric, but there seemd to be much glory in them. He had read of
marches, sieges, conflicts, and he had longed to see it all. His budy mind had drawn for
him large pictures extravagant in colour, lurid with breathless
details.

We can see here the
impression of war that Henry has. War for him is "extavagant in colour" and "lurid with
breathless details," which is sharp contrast from the actual mud and dirt reality of war
that he encounters. We see that for Henry, he enlists because of his dreams of honour
and glory, that he gets a taste of when he says goodbye to his schoolmates and they
"throng about him with wonder and admiration." The "gulf" he senses between them makes
him "swell with pride." Enlisting for Henry is an action that is done for selfish
reasons, for the glory and status that he feels he will gain through being a soldier and
engaging in such romantic exploits as war. He has a lot to
learn.