Offensive weapon, what is going to happen? Weapons, Guns, Firearms

Hi i am 17 and I was arrested the other day for being in possesion of an offensive weapon (knuckle duster), also i was removed from a nightclub that same night for being agressive with the bouncers or door men (didnt touch them in any way allthough they had to restrain me and remove the weapon from my coat). I have been summoned to court and Im really scared, this is my first offence apart from one when I was 14 for criminal damage, I am just wondering what may come of this eg. prison or fine . Thanks edward.

ps. the only reason I carried a knuckle duster is because recently I have been attacked by people in the street and feel somewhat safer with it on my person, thanks.