Hi all,
Can someone give me some advice, a little background

When i was 18 in late 1998 i was convicted of:  carrying air weapon in public place (loaded or not) Firearms act 1968 S.19

I was shooting some tin cans off a bit of wood in a run down, disused car park near my home. the offence sounds terrible but i really thought i was out of the way of anyone. but it seems i wasn't and someone called the police
I wasn't arrested but the officer did take the air gun.  My mother contacted someone at the police station after i had the court date and i got a visit from an inspector (in full uniform, it may have been a higher rank, i just can't remember) he said that it shouldn't have got as far as court but his hands were tide

Can someone tell me if this offence will be filtered? I've looked at the list of offences that will never be filtered and mine isn't listed. 
I had a crb back in 2012 my offence is on there but i believe that was before the filtering system came about.

I have an enhanced DBS next week for a part time job and worried that this will trip me up. Should i disclose it or will i be within my right to say that i have no criminal offences? 

I'm really really worried