Legal Question in Construction Law in California

Taking the second issue first, a choice of laws clause is not a choice of jurisdiction or venue clause. If I have proper jurisdiction, I can sue in an entirely different state under a contract that says it will be governed by California law. The court in that state will then just apply California law in deciding the legal issues in the case. So unless there is an additional clause that says jurisdiction or venue will be in your county, only the general rules of jurisdiction and venue apply. You have not provided any of the information that would be needed to evaluate whether her county has jurisdiction and/or is a proper venue for the case.

As for the mediation clause, you have not indicated that it says mediation is a prerequisite to filing suit. So her attorney has done nothing wrong in suing without mediation. You can demand mediation and if they refuse you can get the court in the lawsuit to issue an order that they mediate before proceeding any further with the case, but you have no grounds to throw out or otherwise challenge the filing of the lawsuit just because they didn't mediate first.

What you can do next depends on the jurisdiction/venue issue. If the suit has been filed in a county that is not the proper venue, you waive any objection unless you file a motion contesting venue before you file an answer to the complaint. So you need to talk to an attorney right away about that issue. If venue is proper where she filed, then you will want to file an answer to the complaint along with a demand for, and if needed a motion to compel, mediation. If the venue is not proper, you will want to file a motion for change of venue and a motion to compel mediation within the 30 days since you were served with the summons and complaint.

I note your zip code is in San Francisco. My primary office is on Spear, just a couple of blocks below Market. If you would like to schedule a consultation about your options and discuss whether you may want me to assist you further, please let me know and we can set up an initial consultation meeting.