My current META for this is just saying "Do you know about ?" wait for their response and if they know we're done! If they say "No" I then ask "Do ya wanna hear about it? Approx listening time minutes!" and respect their answer.

It's about etiquette and giving them a choice. You have to be prepared for them to say "no" to hearing about that thing you'd like to info dump about. It's not that dissimilar to getting consent if you think about it, it's rude to just start shoving your information into their brainhole, so to speak lol

Just found it easier to not talk to anyone, IRL, who I can't trust to not assume the worst things about me.

I mean it's polite to ask what she knows about it first. I mean mansplaining is rude, but it's also just kind of annoying to have to explain things to people who already know it. Much better to have a conversation and skip that part so you can just get to talking on a level playing field.