First of all, leaving family and friends and going to the war needs a lot of courage to do...and after going there if you are going to fight against your own country, first of all you feel guilty for doing such a thing, second of all you will never make it against your own country, because even if you win the war you will feel guilty for rest of your life which is like you lost.... It is a very hard time difficulty for sure if things are going to happen like this
I would probably not fight against but for my country
No they aren't proper to use in writing class they are considered slang. It would show your teacher that your not interested in sounding educated and proper.
Hope this helps!
Determing what language is appropriate by carefully observing and listening to others.