To Disagree or Not To Disagree?

I wanted to do a little exploration this week into criticism and disagreeing with another's point of view. For our last formal writing assignment, we had the option to praise or criticize the author of our chosen article and while I opted out, I was intrigued to the extent that criticizing or disagreeing makes me nervous and how far I'm willing to go to avoid it, especially in person. 

Unsurprisingly, I think that disagreeing/arguing is something that is often taught as a "bad" or "scary" thing for people who grew up socialized as women. Women/fem folks are pushed in the direction of quiet, agreeable, and being a doormat when it comes to opinions or big decisions. I have a lot of opinions, thoughts, and perspectives on many topics, from the silly (like are ghosts real or what the best jellybean flavor is) to the very important (women's rights and police brutality) but I really only share those opinions with those I feel really safe with or people who already voiced their opinions that match mine so I know I'm safe.

This is not to say I've locked myself into a bubble of only like-minded people. I spend time with folks who hold opinions that are opposite or different from mine. I usually ask them about it and listen to what they have to say, I like expanding my worldview and hearing what others have to say. Working on campus also helps to expose me to lots of different people with different backgrounds and perspectives (and I seem to have a face that makes people want to tell me their whole life story without me saying a single thing. It happens so often, the things I've learned about strangers is absolutely wild.) but it's rare that I'll instigate direct conflict. It takes a lot for me to feel safe enough to try to change someone's mind. I have to really be invested in the relationship and want to be closer to that person otherwise it doesn't register as worth the stress of arguing points with them. And even then I'll throw lots of "don't quote me" and "I could have this fact wrong"s. 

This fear of conflict manifests in a lot of other ways that can be a problem; not standing up for myself, not making my wants/needs known upfront, feeling like I need to be invisible on bad days and it's something I want to work on, but I don't know how to start diving into that deep conditioning. How do you begin to undo a lifetime of training to be quiet and "the peacekeeper"?  

I don't want to become someone who argues constantly or talks over others (I hate it when people think that if they just raise their voice and be louder it'll make them right) but I'd like to not be so terrified of disagreeing or sharing my varying perspectives. It feels like that's going to be something I'll run into more as I progress into engineering and academic areas. How do you deal with disagreements or differences of opinion?