How do I make it work with my girlfriend?

So This is not a blame game, I'm no perfect person myself, but my girlfriend has an extreme anger problem and gets easily irritated out of nowhere at me and how I go about doing and thinking about things, and screams at me and says horrible things, I've never once screamed back in our 15 months together. But I simply will not tolerate being talked down to and I've told her that. Also, she's extremely immature. I'm older by 4 years and it seems like a lifetime difference. I'm more old fashioned in my way of thinking and she's more progressive. I never thought I'd ever in a million years want to get married but despite all this I still love her deeply and would like to eventually, but she doesn't think marriage is important and doesn't think it's worth all the effort. I'm her first relationship, and she's my longest relationship and first person I've ever dated that's younger than me.
How do I make it work with my girlfriend?
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