What are the consequences of contributing to delinquency of a minor?

Where were you? If you did not know about the party and never consented to it then that is a defense to the charges. Get an attorney and go to trial.

Contributing to the delinquency of a minor is a gross misdemeanor punishable by up to a year in jail and a $5,000.00 fine. With 40 minors present, you could be charged for each minor, meaning a total of 40 years in jail and $2000,000.00 in fines, if you were to be convicted on all 40 counts and the judge ordered the sentence to be served consecutively. Doubtful that this will happen, but you could still look at some jail time. How much depends upon the facts of the case, and whether the kids who got drunk were in any jeopardy of alcohol poisoning. As for Miranda, that is only necessary if the officer plans to interrogate you. If you were simply arrested, without being asked to give any statement, then Miranda is not necessary. If on the other hand, you were interrogated without having been read Miranda, then the statement(s) would probably be inadmissible, but that does not necessarily mean that the case goes away. There could still be adequate evidence, like the statements of those who were at the party. Not a good situation to be in. I recommend that you hire an attorney.