I am being charged with something, not sure what yet?

I live in pennsylvania. I went to my friends house to have a couple of drinks. I am 21, but the 4 other people there were 19-20. Keep in mind that they had previously obtained the alcohol from some source, not through me. My buddy ran down the street to the convenient store and got stopped by the police, got charged with DUI etc. The cops came to the house, and I left out the back door. They knew i was there because my car was there, and they had it towed. I was told I would be recieving charges of some sort. I explained to the officer that I am trying to work my way through college and stay out of trouble( i previously had an underage dui about 2 years back ). I told him that was terrified of the possibility that i would get charged for supplying alcohol to minors, and he said he would discuss the story with his chief and see what he could do for me. Im just curious as to what i may be charged with or if there is any way to get out of the charges because i technically wasnt evading or resisting arrest because number one, i didnt do anything arrest-worthy, and two, i was never seen by a cop or told by a cop to freeze or whatever.