I have a whole different take than most here, dear Besty (peace to you!), and would like to weigh in, not as a "christian" but just as a person, if you will permit me. Thank you!
First, I think such sensitivies run both ways, indeed every direction... when provocative subjects are broached, especially in the manner here. For example, people who don't believe in God, religion, or "christianity" also tend to get quite "sensitive" when religion is, well, pushed, during what appears to be a purely secular gathering. I have especially known some non-religious people to freak out when Watchtower perspectives were brought by JWs to people who weren't really into religion (though, I now totally understand it - LOLOL!). Usually, though, people like to have some idea that religion is going to come up at some point during the day/evening so that they are somewhat prepared (if they agree to show up for the event).
Here, you not only started out the conversation with a question that had NO choice but to lead into religion (it is usually the default for evolutio)... but was INTENDED to provoke (i.e., "... if Texas had their school board 'under control' yet..."). If you stop and think about it, what kind of question was that really? Here is a woman you apparently don't know very well, yet your question assumes that she, indeed everyone, either agrees with you... or if they don't, they should... that the school board is indeed "out of control." Out of control why? Because the head of the Board is involved in some sex scandal? Because funds have been misappropriated? Embezzled? Because of layoffs and/or not enough teachers? Nope. Because it's trying to remove evolution from the science books.
[Now, before YOU take offense, please know that I believe science is CRITICAL to understanding the world we live in right now. It is physical and understanding the physical universe is imperative to continuing our present existence in it. I do not agree, however, that understanding the physical world is critical, even necessary, to understanding the spirit realm. But that's another thread. Either way, I am not sure I would appreciate having a discussion about it in "mixed" company. It would depend... and I would certainly feel more comfortable if I knew everyone present, as well as their views. I digress.]
So, what did you do wrong? Your question intimated that there was not only something wrong with the board, but with anyone who didn't agree with you. The TRUTH... is that you ambushed this lady. AND... if how you tell it is accurate, it kind of appears as if you totally intended to! Here she is, all ready to enjoy a fairly quiet meal with friends (well, as much as you can with very young kids)... and you basically set her up. Dear one, not everyone wants to discuss politics... or religion... at all... let alone at a secular dinner. And NO ONE wants to be ambushed into such subjects. Regarding ANY subject, actually. You, however, tried to evoke an unsolicited conversation about both... politics AND religion... under the guise of asking an "innocent" question about the school board. The school board, however, was not the issue: her views on the subject of evolution... and, by default, religion... was... along with the "politics" of the school board's attempts.
It was tantamount to you going to dinner with some friends, and having a JW there who asks whether Puerto Rico had its government under control yet and when you ask what they mean, they say "Well, they're violating people right to freedom of religion and free speech. For example, they don't want to let Jehovah's Witnesses do street work there." And you say (hallelujah! in your heart!)... "That's a good thing," and they say, "What, don't you believe in freedom of religion and the right to free speech?" You see where I'm going with this: you really hadn't planned on a discussion of the evils of JW witnessing, and besides, you realize it isn't gonna matter what you say, anyway. So, you tend to avoid these types of conversations. So, you give a cursory answer and TRY to change the subject. But... that tenacious little JW just won't let you.
My point is that while there was nothing wrong with you believing that the school board was "out of control" for what it was trying to do, shoving it (and that IS what you did) in the face of a virtual stranger who had absolutely NO idea that it was coming was... rude... arrogant... presumptuous... and, really, in the poorest of taste. It was not appropriate for your dinner audience... without first discerning whether she wanted to discuss such topics.
In short, it was VERY Californian. And I can say that because I am a Californian (since 1964)... and see it all the time. And it STILL amazes me. "We" tout ourselves as some of the most "enlightened" folks in the country, indeed the world, and yet, we are sometimes foremost among those lacking in even the most basic of manners. We don't believe in etiquette... or sometimes even minimal decorum. As a SIL indignantly said to me recently, when I shushed her for getting in the business of and asking a very personal question about my DIL, "I have a right to say what I feel, don't I?"
The answer to that is, no, not always. You do not have a right to always say what you feel... or ask what you want to... to and/or of whom you want to. Sometimes, it's none of one's business... and other times it's just out of line. Unfortunately, dear one, you were out of line here.
Now, I realize that there are going to be ones here who howl and cry because they believe in that "right" to say what one wants to whomever one wants about whatever one wants whenever one wants... but... they're wrong. That one can DO it... does not make it right... or a right.
I bid you peace, truly, and absolutely NO offense was intended.
YOUR servant and a slave of Christ,
SA