YOu asked:

Can I be charged for a misdemeanor for being at a party where underage drinking took place?
Additional Details:
I am 21 years of age. I did not drink or provide any alcohol for the party. I blew all zeros on the breathalyzer test.

The better question is whether you can be convicted of a crime since anyone could be charged with anything. If this was your residence, and you permitted minors to attend the party and drink, then you could be charged with and convicted with of alcohol to minors. If this was not your residence, you did not purchase the alocohol, and you did not furnish alcohol to a minor, then you would have a good defense.

Stu Shafer