Innocent to a 484(A) - Petty Theft ($35)

My question involves criminal law for the state of: California

I was charged with 484(a)- petty theft, for $35 dollars missing from a purse that I was holding. I am innocent and did not steal any money. My husband is a Captain in the Air Force and we always donate and volunteer. The following are the specific details; I went to use the bathroom in the b2 complex. As I entered, the custodian was still cleaning the bathroom, she told me I could use the handicap stall while she finished cleaning up the others. As I was doing my business, I heard another girl walk in and heard the custodian let her use the middle stall next to me. As I was washing my hands, the girl who used the bathroom next to me, told me “hey you left your purse” I shook my head and told her it wasn’t my purse. She insisted that I left it but I wasn’t even in the stall. I decided to take the bag and give it to the custodian lady, as she was the last person to leave, I figured she would know who it belongs to. I walked out the bathroom and went to look for the custodian. I searched for a few minutes looking for an employee who resembled the custodian. To no avail, I took the purse to my classroom. A few minutes later, I hear the cell phone in the purse, I answered and told the person on the phone that I have the purse and gave her my classroom where I was located. As I waited for the person, the rightful owner happens to be the custodian. I gave her purse and didn’t even receive a “thank you”. I go back to class and minutes later the sheriff comes to the classroom to look for me. They ask to speak to me about the purse, I told them the truth and they told me her money was missing. They asked permission to go through my belongings to look for her “money” I know I am innocent so I gave them permission to go through my wallet and book bag. They found my money in my wallet and inside my daily planner. They told me the dollar bills she described she had, I had the same exact bills, plus $5 more. They gave me two options, to either return the amount of my money to the “victim” and she would drop charges or go to court. I was outraged at the accusation and was not well with words, but the money the cops found on me is mine and its just coincidence that I have $40 dollars in 10’s/5’s and that the lady was missing $35 in 10’s/5’s. It was then that the sheriff gave me a citation to appear in court for petty theft charge.
Additions/Summary:
1) Picked up cellphone and told lady where to find me and her purse
2) My husband talked to the lady over the phone and she told him that she wanted to drop the charges, told both detectives the same thing but they still want to purse it.
3) The detective who wrote the citation put another detective to speak to me at their office and this detective was not present during the citation.

Well, from what you have told us, it seems to be an incident of your word against the custodians. That's going to make it pretty hard to convict you beyond a reasonable doubt. It also makes it nearly impossible to "prove" your innocence. But, it is up to the state to prove your guilt, not you to prove your innocence. If you stick to your guns, I think you are likely to come out on top in court.

I'm curious, though. Do you know who the woman in the other stall is? If so, did you identify her to the cops so that they could question her as well? I ask because, if you didn't take the missing money, she seems like the most likely culprit.