Minor in Possession: California BP 25662A

I'm live Arizona and received the ticket above on Mission Beach in San Diego in July while on vacation, Infraction box was checked on the ticket. I did not have a drink in my hand when the officer on the beach came up to our group. I'm under 21 but most of the group were 21. He asked a few of us our age and cited me as I was under 21.

A letter came from the San Diego court to my home address in AZ with my plea options. I chose to plead guilty and pay a fine of 190.00 on the letter it stated my driving privileges not my drivers license would also be suspended for 1 year in the state of CA. I figured since I don't live in CA that was fine with me. I signed the agreement and sent in my money.

A few weeks later I recived a copy of my check from the court with an altered amount to $75.00 with someone initials on the check and they without my knowledge changed the agreement to an option I did not select which was Penal Code 415(1), "fighting in public" which did not happen. I would have never chose that option even though the fine was $75.00. I was aware of the option as well as the option to plead not guility and opt for a trial. Also on the recent letter it stated B&P Code 25662A requires an automatic suspension of "the license" which was never stated in the plea letter with my options.

I do have a copy of both codes, I don't see anywhere where an automatic suspension of a license is required. Can someone point me on the web where it states automatic suspension for B&Pcode 25662A? And can the court change my plea once I've signed off and sent my check. I would have chose not guilty with trial had I known my license would be suspended.

Can the state of CA suspend my Arizona license for an infraction and can they change my check without my knowledge. The bank cashed the check for 75.00 not 190.00. I'm going into law enforcement I would never agree to PC415(1), I would have fought it.
Sorry this is so long.