I feel I shouldn't be affected by it anymore

My childhood was not the worst. I get how mentally I would get traumatized from it while it occured, but it doesn't make sense how I would *still* feel that way. I was explaining to my new friends the situation since they can, to a certain extent, relate and the first response I got was: move out. Me trying to explain why, lead to a "okay but you have to" and a "if it's still going on, it makes sense why you're having issues"

The problem is, it's not going on. I am not being physically or verbally abused by my dad. I haven't in years, he stopped hitting me about 6-8 years ago (memory is fuzzy), and the yelling slowly stopped when he realized it wasn't "okay" - but he refuses to discuss it further. He acknowledges it, but in a bitter angry way. I am not being bullied at uni like I was in school, much the contrary. People say hi, greet me, talk to me. Yes my relationship with my mother is in the trash, but if I avoid being alone with her we actually don't have issues or arguments. The last big argument was at New Year's, but that was months ago

I haven't told my friends the full extend of it. One of them knows (because I overshare a lot) but since I found out the other one tends to be really open with her mother, I kinda fear mentioning it. Although I am sure if I asked her not to share it, she would - I felt a bit stupid and childish. Even though I'm a legal adult for years now and can do "what the hell I please" as some say, I live under their roof and I am grateful they're willing to struggle with money so I can finish my degree and get a good job once I conclude it. That's a good thing. I feel I owe them since I live without contributing financially, that's more than what some parents can or will do, right?

But I still fear my dad will lose his patience and control. And I don't know how to explain it, especially when I realize I do have good fun happy childhood stories involving him (most of my fun memories do not involve my mother, unless they're the type that ends up with people saying "that is kinda sad, you know?") . How do you explain that despite it not happening right now, it still affects you to a degree you can't act like a normal adult should, because it feels you got stuck mentally half a decade before or more?