My question involves criminal law for the state of: Virginia

I have arraignment tomorrow morning. I was wonder about how long arraignment takes and what exactly happens. I was not arrested at the time of the incident so will I go to jail tomorrow at all? This is my first offense and the amount I stole came out to be about $25.00. I plan on pleading not guilty and asking for a public defender. I don't exactly know how to do this. I understand that Virginia is hard on shopliffters but I was wondering if anyone could tell me the likelihood of me going to jail. I am a full time student and I'm very worried about this part.