Congrats on getting out of High School! It may not seem like it now, but life is about to open many “possible option(s)” for you. So, may the Lord guide, bless and keep you as you walk through His creation.
“Can one still serve Christ whilst fighting/serving in the army?” First, let me share with you that my oldest son serves in the U.S. Military. The educational, occupational, health benefits are excellent. I assume the Brits are similar, so if you go that way and work hard, doors will open for you.
Of course serving and fighting are not the same thing. Is there a Christian worldview that definitely answers the question? Not really, as Sean pointed out there are different viewpoints. So, from my grey beard perspective, allow me to recast the question:
Where would this world be right now, if Christian men (and women) had not fought and died defeating the evil manifested in this world? How much Christian blood has been shed over the centuries to protect our rights to worship Jesus (or any false god) and live freely?
The whole world lies under the sway of the wicked one (1 John 5:19), and his minions would gladly destroy everything and every Christian in this world if given the chance. Like wise, how could Israel protect herself against the enemies that lust to destroy her, if she didn’t have the earthly protection of a strong military?
If someone were to say to my son, or any of the untold number of Christians in the military, “Hey, you don’t serve Christ because you’re in the military,” that would be an incredibly foolish and judgmental statement. It’s what’s in your heart by grace that serves Jesus, not the fact that you’re in the military or not.
Yes, there have been horrible misuses of military might since the beginning of time, but as I alluded to earlier, where would we be right now, if it were not for the Men and Women of God who stood-up when the Lord of hosts mustered the army for battle? (Isaiah 13:4)
So if you choose to join the Army, prepare to work hard - and work for the Lord always! God bless.