Know it all! How to approach?

Has anyone ever had a friend or family member that is a constant know it all? What is behind this kind of behavior and how do you consciously react to it? (Without reacting from a place of annoyance), because I often feel like she speaks to me like I’m a dumb child. What’s ironic is that I’m seven years older, am a Nurse practitioner, and she loudly talks about how she was unschooled growing up and has never ever been in an actual classroom. 😳

So I will call her Olivia. Her son is good friends with my son. We have met up often and she has come to my house a few times. She is constantly spouting off random facts, which I don’t mind during normal conversation, but she also feels the need to correct me or add on to anything say.

Some examples-

-We were at the park with our kids. I pointed out a cicada shell stuck to a fence post. I said “look boys! A cicada!” Olivia said “actually, no Becca, it’s not a cicada. It’s the shell of one. Very common mistake people make.”

-She was at my house and she made a comment on this large maple tree I have in my backyard. I offhandedly said “yes, I love my maple” and she replied giggling, “oh you mean genus Acer? Sorry, I always call things by their scientific names, not their common name.”

-Her son has a lisp and speech impediment that is pretty noticeable. She was talking about it one day. I said “have they referred him to speech therapy?” She replied “who is they? He doesn’t attend public school for obvious reasons. Secondly, speech therapy is ableism. There is nothing wrong with how he speaks, society just pressures everyone to speak the same.”

-I was eating a sandwich once we took on a picnic with the kids, she stopped and said “did you know the tomato you’re eating is genetically engineered and original tomatoes hundreds of years ago were completely different? Also, tomatoes are not even that healthy. I don’t know why you’d eat one. You can receive the same exact nutrients from vitamin fortified bread!”

It’s just random snippets like this that are so obnoxious. There are other things too, like she is absolutely convinced that all three of her children are autistic and have genetic syndromes, that a multitude of doctors have told her NO, they do not. But she says “the doctors are against her because she’s obese”. I told her that as an NP I don’t see any autistic traits in her children, and she scoffed at me.

I am trying to approach this with compassion because I think a lot of it comes from deep insecurity about her competency because she never attended school, but I need some help as to what exactly to say when she starts showing her ass like this.

Advice?