My husband had a conviction for criminal speeding at the age of 18, and he also had a dismissed charge for an assault (long story, but basically someone lied then admitted it), and so far it has not been a problem. It would have been however had we lied about it. We did have to submit court documents about the arrest, and a little blurb about it, and that was it.
Also talk to your SW. I spent so much time worrying about it, but come to find out it was not a big deal (easier said then done I know
)...
Good Luck