How am I charged with Cl 4 Felonies and what will happen?

I was out cruising around with some friends one night and they pulled into a abandoned building where a a gas station used to be. We went inside and they began talking about lighting the place on fire. I immediately left the building and demanded that they take me home. (15 miles from where I live). They exited the building a while after me with the place ablaze. They then drove across the river and entered a second building and lit it on fire while I remained in the car pleading with them to take me home. They finally took me home and then returned to the scene to watch the fire trucks put the buildings out. One of the kids name was brought up later after he went bragging and was convicted and sentenced. He served three months in prison before the states attorney offered him a letter granting immunity if he told what happened at the buildings. I am now being charged with burglary (cl 4), arson (cl 4), and two aiding and abiding to arson (cl 4). Do these charges hold any ground? What did it mean when he was offered immunity? What do you recommend? I was questioned twice about it and both times I respectfully refused to be questioned.