Could the woman who refused to serve you have done it because she didn’t like the way you look or was disgusted by who she thought you were?
The passport should be sufficient. You probably only need a few months residency to be a citizen of the state, but you have to check state law for that. At a maximum, you might need a year’s residency in some states in order to qualify as a citizen and be able to run for political office or get state benefits. Just google your state’s residency requirements if you care.
You need not get a driver’s license. That makes no sense. I suspect that if the woman was not malicious, then she was an idiot. Usually jobs like hers are patronage jobs and the only requirement is that you know the right person. They often resent having to do actual work, since they feel entitled to be in a no-show job.
Go in and act like you know what you are doing. Even better, research it, and then go in. You could threaten to bring a lawyer. But what might be better is to go to your local legislator’s office, either the municipality legislator, or your state rep, and ask them for help. They usually have juice, and they live to help constituents. You might even get the fingerprinting done for free.
Third, you could actually hire a lawyer.
Fourth, talk to the local criminal folks and ask them to help you out by breaking that sheriff’s office idiot’s leg. Then let the replacement help you. All the while tutting about what happened to her predecessor. What a shame.