Hi again Zac.
If you don't end up owing taxes, then you don't need to make estimated payments. Some years it might be a good idea to increase your withholding slightly because you have multiple jobs, but if you aren't owing at the end of the year, it sounds like you have it under control.
An LLC, a Limited Liability Company, is a legal, rather than a tax, construct. Here is some information from the IRS on the topic: https://www.irs.gov/businesses/small-businesses-self-employed/limited-liability-company-llc.
Based on what you have told me about your situation, it doesn't sound necessary. But I don't practice law in California, so you might want to have a brief consultation with a business lawyer to see if there might be advantages under California law having to do with issues other than taxes.
All in all, it sounds like you are in good shape. Keep it up and let us know if you have any questions in the future. Thanks for stopping by to our event!
regards,
Annette
