This is the issue I've seen time and time again. You were sensitive and took her concerns seriously. But IME any form of conciliatory gesture is simply viewed as 'weakness'. (So glad her complaint went nowhere).
This is exactly where #BeKind has got women. It's in no small part of the reason that I no longer for one moment entertain it. I use few words, and am as terse and to the point as possible. The less you say the less they can twist. Three words: 'pronouns are optional' is all she'd have got out of me.
Even my employers, who are up to their nuts in allies and sport rainbow flags and lanyards everywhere, don't make pronouns mandatory, albeit it's strongly encouraged. I, on the other hand, am well aware how dangerous it can be to 'out' a trans person, am well-versed in protecting young trans people (some of whom are very vulnerable), and will pull out all the stops to offer them support. For my views about not announcing pronouns, or involuntary trauma responses as a twice rape-victim when in vulnerable situations with natal males, I'm brushed off as a 'transphobe'. Would they rather I continued to protect gender questioning people as above, or signaled my compliance with rainbows and pronouns?
There's so much navel-gazing bound up with this whole self-involved movement - part of a much broader picture of identity politics - it's beyond tiresome. In reality, your identity is of zero interest to anyone other than you. For my part, I couldn't give a bison's bum how anyone else perceives me.
As for 'guessing' pronouns, people have been doing this with mine for 40+ years with pretty much a 100% success rate. Other people's comfort and wellbeing does not come at the expense of my own. If I'm asked for mine again, rather than responding with a coy 'that's not a practice I follow', I might be tempted to say 'surprise me!'