Why is it still weird to talk sex with my mom?

I am 22 year olds and I just made a gynecology app for the first time in two years (bad I know), my mom asked why I needed one. I told her for an annual checkup also to get tested for STDs just in case.

She said “why you’re not having sex right?”

And I said “yeah actually I am...”

and she said “but you’re not in a committed relationship!!!”

And I said “you don’t need to be to have sex...”

Which was clearly not okay with her, she sorta flipped out but all I was thinking was that I’m being safe, getting tested, and I’m a grown ass woman.

It really sucks to be this old and still feel so judged by my mother about the things she should be approachable about. I’ve never felt comfortable talking to her about sex, which led to an insecurity that I’ve recently come to terms with. I now feel like I own my sexuality and I’m not ashamed of it. Now I don’t know what to say, should I say anything? Any advice?