I have 2 counts of contributing to delinquency of a minor, can i get it expunged and how?

i was about 18 or 19 yrs old and the cop pulled us over and found cigarettes on the girls with me and they blamed it on me. so, guess what, i got charged with 2 counts of contributing to the delinquency of a minor. i did 6 months of probation and community service and paid the fees. thats all it was and i havent been in trouble since. please help!! because i need this off my record or something because i cant get into a subsidized housing place without it. Thanks