Is that a text by Tolkien?

[GafferGamgee]

Years ago I read an english text about a young poet, who knows war only from stories and he dreams of being "worthy to go to war" with the kings men.
One day that happens and he finds out war is different, in the first battle one of his best friends is killed and the text is about him reflecting about this.

The text is not about middleearth, but about some time on our real earth as far as I remember. Nevertheless I think the text might be written by Tolkien, but I am not sure. Do you know a text by Tolkien about this topic?

Thank you so much!