Arizona law punishes the conduct of misrepresenting your identity in two areas: first is the use of the fake identification to do something ( trying to get into a club) and second is the tampering or falsification of the actual identification card. You could be prosecuted for a number of different crimes under Arizona law using the fake identification, including Criminal
Impersonation (ARS 13-2006) and Forgery (ARS 13-2002). Both of these crimes punish people for assuming a false identity or pretending to be someone (or some age) that they are not in order to get something from the person that they are deceiving. If you have also actually tampered with the identification yourself, ( changing the birth date), you could be charged with another crime like Tampering with a Public Record (ARS 13-2407). This punishes the act of altering or changing an officially issued piece of documentation like a driver's license.
All of these crimes are felonies in Arizona. Felonies are crimes that are punished by time spent in a state prison, usually in excess of one year. Criminal Impersonation and Tampering with a Public Record are both Class 6 Felonies, which are punished by 6 months to 1 1/2 years in jail. Forgery is a much more serious crime, a Class 4 Felony, and is punished by 1 1/2 to 3 years in jail.
You need to wait and see how the charges are filed against your friend. If she just received a ticket with a notice to appear on it, the charges could be filed as a misdemeanor. Normally, for a felony offense, a person is taken into custody. The court will look at the circumstances surrounding your friend case. If this is the first time your friend got caught doing this, the court may look for a probationary sentence, fine and court cost. If the sentence is going to lighter, the way the case is filed, will dictate the options available. You may want to hire an attorney to look at the facts of the case. In doing so, they may be able to find flaws in the State's case, which could persuade them into amending the charges, to a lesser crime and punishment.