I am in the Marine Corps and over the weekend I took alcohol to a friends house, he is 27 years old I am 24?

and my date was 22. A 19 year old which is my 27 year old friends wife, consumed some of the alcohol after my departure. I didn't coerce her, hand her any, nor witness her consuming the alcohol. Today I was read my rights and questioned about the events of that night. Cops were called after I was already home and she was charged for possessing alcohol under that age of 21. Some how it's coming back on me, when her 27 year old husband has a liquor cabinet at the home where the 19 year old lives, alcohol his always present in their home. Does this seem shady to anyone? I feel confident that no punitive action will be taken against me, but they have started formal proceedings. Am I innocent here? Keep in mind the Alcohol was provided for 3 individuals over the age of 21 and it was not my home that the alcohol was consumed in, nor was I even present. Would a Alcohol delivery worker be charged if he delivered the alcohol to a legal drinking age person and that person later allowed the alcohol to be come into possession of an under 21 year old? It seems shady to me, any advice would be appreciated.