How to stop being non-confrontational?

I used to associate confrontation with getting in people’s faces and being abrasive, however, I’ve realized it just means setting boundaries and speaking up when necessary.

I am a “people pleaser”. Not for malicious purposes, but because I’ve always associated disagreements with negative outcomes (my parents would blow up at me if I did or said anything that wasn’t to their liking). I never want to disagree with people, feel like a burden, or create an uncomfortable environment. This has only lead to me being a doormat and trading in my comfort for the sake of “peace”.

Today at work, a coworker I’m not particularly fond of made yet another offensive and ridiculously inappropriate comment to me and all I could do was nervous laugh (and I’m panicking that she interpreted this as me agreeing with her). This coworker is always gossiping, talking about politics (we work a government job where this is not allowed), talking very subtly about minority groups she doesn’t like, half asses every task she has, etc.

She’s under the impression that we are friendly because I when I first started working, we would occasionally chat about normal stuff like what we did over the weekend, good restaurants to eat at, etc. I’m assuming she thought it was safe for her to start ranting and gossiping, and me being the spineless coward that I am, never disagreed with her or told her she’s being inappropriate.

I’m worried it’s too late to tell her I don’t feel comfortable with her behaviour.

This is an issue that has affected me a lot throughout my life and I want to learn how to respectfully confront people when they make me uncomfortable.