If i have an a.c.o.d. case and completed the probationary period are the charges considered dismissed?

i was arrested when i was 17 (i'm now 28) for petit larceny. I was tried as a minor, the case was a.c.o.d. and i completed the probationary period with out incedent. now i'm thinking of changing careers, and want to know if a job within law enforcment would even be a possability.