IANAL but if you purchased the ticket in California, California would take jurisdiction.

A fairly important point is understanding exactly why AA denied you boarding in DFW. This is not a negligence case, in which case you would have to show that AA failed to exercise a due standard of care, but a breach of contract case.

Look up the terms of the contract of carriage with AA. It may have an optional arbitration provision. While many people say that litigation is more consumer-friendly than arbitration, that's often not the case. Arbitration can be fairly expensive for the company and cost the consumer little or nothing. I have had three times in the past seven years when I threatened arbitration against a large corporation, and each time I got a mid 4-figure settlement without having to actually go to arbitration. (In one case I had to pay $200 to file it.) OTOH, I don't know how it works in California, but small claims court often has a "home field advantage." You, and your sisters and your cousins who you reckon by the dozens and your aunts (theatrical reference, HMS Pinafore) may vote for the judge who is hearing the case. AA doesn't.

Irrelevant sidebar, one of my cases was against a high-profile company who was in the news about every other week for committing some breach or other of public trust. I had a good time while I was negotiating with the company's attorney adding point after point to my Powerpoint presentation for the arbitration on why you can't trust a word the company says. Lots of stuff matters in litigation that doesn't matter in most cases. But if you do go to small claims court, expect to be allowed to present about 5% of what you were planning to present. Because the judge isn't going to look at the 27 eight-by-ten color glossy photographs with circles and arrows and a paragraph on each one explaining what each one is to be used in evidence against them.