If you "served" your sentence i.e. you went to prison and served your time or paid the fine, im pretty sure it was said you do not have to state any served sentences on your application. Try using the online chatroom with the army recruiters for advice on it. Relogin under different username and ask the same question to several different recruiters to confirm.
Yes it can. Especially theft. You should talk to your careers advisor. I believe the wording is "unspent criminal convictions..." so I'm not 100% certain where you stand.
Just ask your local army recruiting place. You could be OK, but they will ask you why you did it and grill you mercilessly. If you cant give a good enough awnser they may boot you.
Just be honest about it and dont try to hide anything. The Army is into integrity in a big way so if you can hold your hands up and say yeah I fcuked up that'll be a tick in the right box. If youre open and honest you'll be treated fairly.
If you have a fine, then you already do have a criminal record. If this only happened last year, the conviction is still 'Unspent!'. It does not become 'Spent' until after 5 yrs for Non imprisoned convictions, and longer for sentences to prison dependant on crime. Due to the time scale I would definately put it on your SC form. shoplifting is a dodgy one for the forces as you could turn out to be an opportunist theif in your unit/on tour (Not my opinion, they may just think that). It literally a 50/50 gamble but you will get caught out if lying as you have more than 1 check throughout your career. Be honest with your AFCO and good luck!