There is a substantial probability that your deferral will be revoked and you will be convicted of the charge, which is a criminal misdemeanor. The penalty is otherwise relatively minor for a first offense:
Quote Quoting Colorado Statutes § 18-13-122(b)(2)(I)
Upon conviction of a first offense, illegal possession or consumption of ethyl alcohol by an underage person shall be punished by a fine of not more than two hundred fifty dollars. The court, upon sentencing a defendant pursuant to this paragraph (b), may, in addition to any fine, order that the defendant perform up to twenty-four hours of useful public service, subject to the conditions and restrictions of section 18-1.3-507, and may further order that the defendant submit to and complete an alcohol evaluation or assessment, an alcohol education program, or an alcohol treatment program at such defendant's own expense.
If this is a hearing on your probation violation it is likely that you will be resentenced on that date.